First of all, i must say that i hate spam in chat room, that's the main reason i never bother other countries with my player ads, but i understand that GKO rules allow spamming, as long as it doesn't become into flooding so i had no choice but to live with it. However as Brian pointed, people is creating messages without using the player code, so those messages can't be filtered and their messages are displayed, that is a lack of respect to others IMO: People is using their right to spam, but avoiding the player filter, people abuses.
I discussed about it sometime ago with argentinian managers, we used to avoid using spam in chat rooms, but with time (and zero control), users started to spam, then they started to spam avoiding the player code, their reason is simple: i can't sell my players, market is too hard, other users will keep spamming with that method, no matter how i behave, so i lose selling chances.
That said, i think that moderators should have an active role in chat room: Just give moderators tools to control chat rooms, they should exist for a reason, not just to move/remove topics in forum. Let moderators act: they should be able to warn spammers with GKO rules and ban them from chat room/contact GM with proofs if the spammer continues braking them, so GM can decide what to do. People will keep braking rules/avoiding filtering until somebody do something about it!
Just don't give me wrong: I don't think spammers should be inmediately banned from the game, restrict their access to foreign chat rooms should be enough the first time they brake rules after warning, if the spammer repeat their behavior, a more serious punish should happen.