Our school could really use little swiper-things on every door so that people could swipe their student ID cards and gain access. This would allow for much greater prosecution of theft, as it would be clear who was where. It would also allow people to be granted limited access to somewhere.
For instance, the Music Teacher could let a few students have access to the theatre and concert hall on weekends. These students could swipe their cards and get in to use the facilities for composition or practise. If anything was disturbed, it would be clear who was in there over the weekend.
It could also be used in residences. This would prevent theft from people outside the residences, and it could even be made more complicated: between the hours of 8-3 daily (the school day) identification would be required every time the door was opened, except that it would last for say 20 minutes. The houseparent's card would have access to every door in a house, and the people in a room could request their doors be locked for an entire day or weekend if they wanted.
In my opinion, this implementation of already-existing technology (and our ID cards already have a barcode on them) would be extremely beneficial.