I'm the minority here, but yes, i locked my kids in at night. i did not do so for naptime and NEVER as punishment or to get private time for myself. My kids are 13-14 months apart and the day I brought my son home from the hospital, my daughter learned how to climb out of her crib. She has been a walker&climber from age 8 months. She would stack stuff to get to what she wanted. I have photos of her at 9 months climbing a rocking toy to get high enough to look out the window. At ten months she was on the dining room table!!! Of course at 10 months she had no idea about how high she was or how hurt she could be. We first tried a baby gate, but within 5 minutes of installation, she was up and over and this was the extra tall kind. So, we made the decision that the most safe way would be to lock her in and teach her that she could call out to us and we would respond. We installed two video monitors, one for my son's room and one for hers. i was worried she would not only get out of her room at night and have access to things not appropriate like in the kitchen, knives etc...., but also worried she would try and be with her brother. At 13-14 months old, that just isn't safe. As for emergencies, most kids die in fires due to them being scared and hiding and at least we would know that they were in their rooms making the search easier. I am the safest mommy I know too, I baby gated, i strapped everything to the walls, I put medicines in locked cabinets up high, I locked all cleaners up. I used electrical plugs, covered wires, stove protector & lock and toilet locked. If they made it, i used it.
Locking them in was the only way i felt safe enough to sleep. I was not open to having my kids in bed with me because I roll like crazy & would be too scared i would smother them accidently.
Now, with that said, I never locked them in for time outs or anything else other than bedtime. It became our routine and we made it clear to her we could hear her & see her. We showed her the monitors and she got it, she would wave at us often. We taught her to just call out and we would come and we did every time she did. We already had good bedtime routine down, so she was used to sleeping in the room with the door closed while in the crib and she was use to having to call out to get us to come, so nothing changed in the routine other than her bed went from crib to toddler bed and she learned at night, she couldn't leave her room. I baby proofed her room and the video monitor was great cause we could see her without having to go in there, we could see her great with a night light on. Once she was potty training, we just placed a little potty in her room beside her bed and that worked great when she woke up to use it. Once she was 3 and her brother was 2, the locks came off as we could trust that they would not hurt each other without us hearing something and felt they knew better than to be climbing around in the kitchen. they are now almost 5&6 and I'm very happy with our bed time routine. We have them put on pjs & brush their teeth, then my son goes into his room and into his bed and we do hugs & kisses and my daughter goes into her room and her bed and we come in and do hugs & kisses. 5 minutes tops to say goodnight and say prayers.
To this day, they call out for us and I have yet to find them up and about at night. When they have been sick, they have gone to the bathroom and holler for me. I'm there in seconds.
I also was the mom who used the monkey back pack leash thingy for safety too. I had a newborn and a 14 month old who had been walking since 8 months old. I couldn't always carry both and my purse and diaper bag into a store especially if i was returning something. if I got the stroller out, how was i to push a stroller and a cart to shop? So I leashed my child and she was able to learn limitations in a safe manner and I got looks from those who felt I was treating her like a dog, but ironically those looks were never from people with two young kids.
So, i say do what works for your family because you know what is right for you and yours and don't not do something for fear of what others think if it will work for you. Only you can say if it is right or not. Best of luck and hope you find a solution that works great!
ADDED:
After seeing so many others posting about neglect, abuse, child being scared, alone, crying etc... I would like to say that i never had any of that. Both my children from day one slept in their own beds and around age 4 months, were moved into their own rooms. They learned how to go back to sleep on their own and neither of them really had trouble sleeping thru the night once asleep. we had a few bouts with my son sleep running and after he ran thru the house at full speed and crashed into my nightstand and almost knocked himself out, we debated about locking the door again, but decided against it since he was potty trained and I didn't want to set him back in that, so I added chain locks on both doors going outside so while he could open them, he wouldn't be able to get outside. So far so good there. So neither of my kids have been traumatized by it and as i stated above, both have a very healthy attitude about going to sleep in their own rooms in their own beds. i have one friend who slept with her daughter until the second child came along and she is still having trouble getting her to sty in her room and she is almost 6. my other friend whose daughter is 6 can't sleep without her mom being in the room and if she wakes at night she screams until mom returns who sleeps in the room till she is asleep again. Learning how to fall back asleep on your own is like the first thing an infant should learn in my book, otherwise it seems that these two girls are more affected and have more sleep issues than mine and both these other girls do not play alone in their room, but my daughter is very comfortable playing in her room. Her room is her comfy area as is my sons and neither have an aversion to it. neither of my kids are scared of the dark or have those issues either, or at least not yet. they feel quite safe and secure. One poster put on here that parents need to be careful since little ones are so immpressionable, i'm sure they are right, but I was making sure they would grow up enough for it to matter. If she had killed her brother just trying to love him or cuddle with him what then? How would she ever forgive me for letting her have that access to him because i trusted a 14 year old not to leave her room? As for the chimes, well let me just say that if you can't sleep cause your worried and you get sleep deprived and then finally sleep, those chimes may not wake you and trust me, my husband could sleep through an earthquake and tornado at the same time!! Our children were used to the door being closed at night, they knew nothing different, so it wasn't odd for them. once we put them in the toddler bed I think they got up 2-3 times. Otherwise they went to sleep and never thought twice about it. We already had a routine and so they were in any distress at any time. So while I know some people may use the locks for selfish purposes, please hear them out before labeling.
As for Bridget B. - if you have trouble with your child staying in her bed or being comfortable in her room, obviously using this method would not be for you. I personally wouldn't have used it if i had not needed too and I do not advocate using it for any purpose other than safety for the child or safety of a sibling etc... i just felt i needed to clarify....I tried to concieve for 11 years before adopting my daughter and there is nothing I wouldn't do for that little girl and that includes getting up 1,000 times if needed and after you go through such a long journey to be a parent, the last thing you want is time away from your child, but we as a couple decided after talking with so many other parents that setting good sleep habits from the get go was the best thing ans we did and we stuck to it. Finding out I was pregnant when she was 6 months was not even conceivable much less planned and having to be creative and adapt was challenging and rewarding. My kids love each other greatly and play nicely and i wouldn't want it any other way, but their ages did pose some huge challenges especially with them being so mobile so young. Just be kind, be thoughtful, and supportive. Different isn't always horrible and there are many colors besides black and white. Ok, I'm off my soap box.