Athania
Sure,but if you keep the spare key,you can tell her you stop it,make a copy of the spare key and keep both until you find someone else to keep one.But you should always have a spare key(it would avoid an embarassing situation when asking someone to cut the belt or pick the lock...).
Angelina
Oh yes,often,even if I've always managed to not do it until now(especially as I know it would mean,not only a very severe punishment(including spanking and very strict grounding)and not have access to the spare keys so easily anymore,but as it would mean too to not be allowed to have any contact with Emilie during a long time,and way less privileges for us after it...).But it happened more than once that I had the scissors in hand,in front of the boxes,trying to decide if I should open the one with the key to my chastity belt or not.
Until now,I've always managed to not open it,but I can't tell I'm sure I never do it...Even if I know I would regret it quickly after it...