gate crass
A 'civilized' and pre meditated form of gate crash. Having not been invited to an event seeks out invited guests to get in sideways,through invited guest, knowing they are not wanted by host yet knowing it would be too akward for host to ask them to leave
Jane is having a lunch,close friend only. Sue is no longer friendly with Jane, but hates missing out. She finds an invited guest and 'gets a lift' with them or says she will meet them there. Thereby a successful gate crass has artfully been arranged.