So I guess u would'nt be from the business side la.
Anyway its not a matter of which sector to trust la. come on some if not most of the students are very young to even consider trustworthy.
Esp since u are carrying such a lump of money around.
Not that I condone "their" manner and approach, however where and when money is concern, best to practised discreet.
if u reallie suspect that it is the TEP students from Lifestyle, u can approach the lecturers in charge. FYI, there are cameras in Lifestyle and u can see the the booth of the SingPost.. =)