I will admit it is … less restrictive there… even the quest dialog has some terms you wont find in WoW.
However, like the Moongaurd thing, i think it depends on the server itself. I have not seen any mentions of brothels or blatant advertisements of ERP on Siren, but there are things like “Visit our Pub/Bar/Tavern at such-and-such guild housing for drinks and entertainment! Our wait staff is available to service your every need”
which may or may not be stuff like that.