A possible solution to this for fute RR's is that each person would be required to make a scan of the pages of chips as they arrive. These scans would be sent to the organizer of the round robin.

This way, each person varifies what he/she gets with a scan. Once this is in place, nobody can sneak crap chips in without it being caught. Trade ups would also be caught.

I think if I do another round robin, this is one thing I would require. I would probably also only make it open to club members.