Distance walked as exercise is one thing; I have no problem with that. Distance walked in street clothes, just going about your business during the course of the day, seems quite a bit different to me.
twood, what you want to do with your nike+ is ultimately your business - it's your training tool. If you choose to upload miles from walking around campus because you want to have that data then so be it. (Personally, I don't see any training value there so it's not data I'd want, but that's just me.)
Again, I realize this is mostly just for fun, but given that there is a competitive aspect to it, I'd have liked to have known the rules of the game up front. Anyway, as you said, there's nothing to be done about it now.
and for the record, there are people who run 200 mpw.

but not many.