It's likely that you've all tinkered with the community developed FXAA Injector that was released mid November 2011. It enabled a sharper, more enhanced AA with relatively no configuration from a user perspective. It did however present a Punk Buster concern as it literally "injects" code through the BF3 executable. Thus far all Punk Buster has said is that they don't support the injector. But they haven't given BF3 players any reason to believe they'd be banned for using it. Well for those of you have erred on the side of caution and opted to not use the injector DICE may have something that will give you peace of mind, in the near term. Keep your thumbs crossed!
