Some time ago the "Investor games" polluted the Games board.
The best option at that time (and I doubt that it'll change) was to contain them into a specific sub-board, where people will go on their own risk. You know, freedom of speech, too much hassle to keep removing the threads and so on...
Whoever don't want to see them, can easily ignore that board.
A proposal was that the board is by default is ignored, especially for the new users, but I am not sure that actually happens.
I think it's not ignored by default, at least, i haven't touched those default settings, and i see scams on my "Show unread posts since last visit. " on a daily basis.
About the topic itself: like NeuroticFish already said: scams will not be removed due to free speech and stuff, so it's better they can at least be moved to a subforum where it's clear for everybody that there is a high risk of losing your coins if you accept any offer that is posted on this subforum.
For all i care, i wouldn't mind if scammers where banned, and scams removed, but i'm a guest on this forum, so i don't make the rules