Binvite

A type of invitation to any social event sent out of sympathy, to avoid discrepancy or to simply make up an attendance number. It is sometimes sent in the hopes that the invitee will simply decline and throw it away, which is what should be done if sent one regardless of it's purpose.

Dave: What the? Kat sent me an invite to her 18th.
Mike: But you guys never really speak.
Dave: I know right, I totally just got binvited!