invitational entrapment

A social booby trap, usually set on purpose by a host intent on making sure you're available for their lame or otherwise undesirable event; most often set in person, in the flow of an otherwise harmless conversation. One should be on the lookout for this trap, and have a few handy excuses on hand to preempt or avoid making oneself unintentionally available. Trap is most effective on the honest, the sympathetic, and otherwise nice folks who can't just say "F**K off!"