Feel there is a lot more to this story than the OP said....All parents make little mistakes here and there....And perhaps the OP is trying to find something to remove the children from the home ?????...Child custody case?....
If both of the adults were in the bedroom with the door locked...over and over...then surely all the Mother had to do was unlock it...even post a sign on the bedroom door...."Do Not Lock!"....in case the boyfriend is so absent-minded....or just won't listen....and stay out of the bedroom to supervise the children while they are at home.....So I do feel the Mother is at fault here also....
Taking a nap or even having sex while small children are at home is very risky....
