"Doing this would be rude and harm my social standing" is a perfectly reasonable criteria.

Consequentialism should point out that if they offer to split the $100 evenly, and everyone else in the group is somewhat rational, then they've avoided that consequence (and, as a bonus, prevented some jerk from knocking it over and keeping the $100)

Does remind me of an example from my childhood, though: http://lesswrong.com/lw/b4f/sotw_check_consequentialism/67uf