What would you call a invited person who comes in a restricted party hosted by a fellow collegian and then invites most of the uninvited members in the college and apparently blatantly shows off his generosity and the party as if his own?
That is, he invites others to party and says "feel free to have food" (the food which is limited due to restriction on invitees) and moreover it appears to the uninvited people who come to the party that he is the host of the party.