DoJetDriver seems to be making the point that you never know who's around, and it's best to play things on the safe side. God knows I'd like to NEVER turn down a free beer, but public and professional perception of pilots plays into things. Could be another pilot, could be an FA or gate agent, could be a frequent flier from your airline who overhears that you are a XXX pilot on the J/S. I've actually heard people say that pilots should never drink! Better to play it safe. Gotta go now, just enough time to get in one last drink before pushback!