This is a huge security issue. I imagine that someone post this on Facebook and encourage others in the same school (on same wifi) to log in to their AppleID. I

This is a huge security issue. I imagine that someone post this on Facebook and encourage others in the same school (on same wifi) to log in to their AppleID. In this way you can access other people's accounts directly. Buying things at store.apple.com, AppStore, iTunes.