A FlyerTalk Posting Legend
Join Date: Sep 2009
Location: Minneapolis: DL DM charter 2.3MM
Programs: A3*Gold, SPG Plat, HyattDiamond, MarriottPP, LHW exAccess, ICI, Raffles Amb, NW PE MM, TWA Gold MM
Posts: 102,617
I'd insist that the person move and also ask the FA for some extra wipes to "sanitize" the seat. If the poacher is embarrassed by the fuss or potential delay, good! There's no reason for the OP to allow some random person to steal his/her C+ "upgrade".