This question regards player of both games and asks for their opinion:
Do you think bribing Barb cities with diplomats is ok? House rules don't forbid it, on the other hand, they don't even forbid to bribe European cities (like Hamburg and other super-power cities). Bribing also is extremely cheap. My opinion would be that - if bribing should be allowed, then only Barb cities - but even in this matter I am not quiete sure.
What do you think?