According to Bar Society's Facebook page moderator,
Facebook sets an "alcohol" tag for each account which is designed to indicate whether the user is suitable for alcoholic consumption. However if your birthday is hidden this tag is sometimes inaccurate, which results in blocking. While this is outside of our control, we are working diligently with Facebook to resolve this issue. We thank you again for your patience.There's been no word on how many people were banned, but Roiworld's April study on online social networks says Facebook is the most popular site among teens, beating out YouTube, MySpace, and Twitter. On top of that, a majority of those teens go on Facebook just to play games. For Bar Society's underage players, "sincere apologies" were given, but many, including some parents, responded by pointing out the hypocrisy of Facebook policy, where games like Zynga's Mafia Wars are still accessible to minors. This proves, at the least, an inconsistent enforcement by Facebook of its own rules, though much of these rules spring from the federal Children's Online Privacy Protection Act (COPPA), which was adopted in 2000.
Can these arbitrary rules be enforced? Not really. Anyone can set up a Facebook account and fabricate an age. It's more like Facebook is going through the motions to avoid any legal hassle.
For developers looking to avoid a Bar Society-style shutdown, there's a filter that can be used to block underage gamers. I gave this filter a test drive by setting up an account as a 13-year-old. Sure enough, Bar Society didn't allow me to play (and neither did the cannabis-growing, FarmVille knockoff, Pot Farm). Mafia Wars let me right in, though, and if you want to ignore all the bits about gunning down bouncers, bribing government officials, and collecting vodka and rum drinks, well, don't be surprised if you're called out as a hypocrite.
My suggestion? If the developers behind Bar Society want a wider audience, they should consider creating a Bubble Tea game -- a sim for those Taiwanese/Chinese cafes where they serve fancy, little cakes, non-alcoholic milk teas and syrupy drinks with tapioca or jellies in 'em. God, that stuff is good. And, it and can be served -- hassle-free -- to gamers of all ages.