prohaska if you don't show up to the social in columbia i will put you on the bad list.
kidding, kidding.
helps to get to know people, but nobody holds it against you. we know you're all traveling and it's hard to get to them. that said, it benefits you to see how everyone interacts and if you fit in with the group. i definitely would not cancel an interview for it unless you think it is seriously someplace you want to end up and the other is low on your list. talk to the prog coord also. if it's super casual and you can wander in whenever, then cool. if it's structured and you're going to look like a douche walking in late, skip it.
cheers.