I have been in this situation too and tried to do the ‘polite’ thing and sit somewhere else. Then of course another group comes along and I am in their spot. So

I have been in this situation too and tried to do the ‘polite’ thing and sit somewhere else. Then of course another group comes along and I am in their spot. So now when this happens I refuse the suggestion and ask whoever is in my seat to move to their original seat. It’s the only proper solution to this problem.