I think the anonymity thing is hard to get right sometimes... I saw a guy from work at an open AA mtg, and another from my RAW's outpatient rehab. My boss is 20yrs in AA, though I'm alanon we often talk shop, she mentioned once she could put together a pretty good AA meeting any given day of the week just from other people she knows from work. The trick seems to be restraint of pen and tongue like BillW said, given that its the easiest thing ever to talk about others you know and find common ground.
A good friend of mine at work got his 1yr chip in AA back in August, he walked in on my boss and I once during a "shop talk" session of ours- the introduction was delicate though neither of them had a problem being clear about their AA involvement so it didn't become an issue. OTOH if either or both weren't comfortable I can well imagine difficulty.. which I guess is why anonymity is made such a priority.