i'd tell them to get lost to be honest. i used to drive about loads as i wasn't a big drinker but i hated people having no respect for my car, its worse when they are pissed and you are not!
my excuse... its a 3 door, i have long legs so no, i can't move the seat forward and if you don't like it, get a taxi!
(i have even said this to my close female friends)