what about getting one of those alarm things you can turn on/off so if she does open the door you would hear an alarm in addition to the childsafty thing for the door handle?
a link:
http://www.mypreciouskid.com/wireless-door-alarm.html
alot of people use them if they have a pool as well. It will alert you the door has been opened. Ive also heard of people putting them in cabinets they do not want their children in.