Posting is now enabled with a minimum karma required of 20 - that is, you must have gotten at least 20 upvotes on your comments in order to publish a post. Or an adminstrator such as myself or Robin (by default you should bother me) can temporarily bless you with posting ability - in the long run this shouldn't happen much.
I think blatant attempts that /admit/ they're trying to game the system shouldn't be voted down. After all, they help the rest of us become more aware of the different ways to game the system, and therefore help refine it to avoid such ways.
Strictly speaking, is the potential for gaming the system even really a problem? Someone who is successful in doing so gains nothing other than the ability to post, and as Kaj posted out, gaming the system is likely to be more difficult the more important the "reward" of posting is considered to be. Further, Eliezer mentioned that the free karma for posting is unintentional but low-priority, implying that people getting free karma isn't exactly a big deal here.