Great story, and i applaud your tact in the situation. I think along the same lines - don't call it out unless the guy is a douchnozzle.
On a recent trip to boston i was sitting in a bar at the airport and the bartender was talking to a guy about his Breitling. The guy took it off and the bartender looked at it for a few seconds, then handed it back without saying anything. I could see the cheapness of the bracelet from where I was sitting - all the while wearing my Breitling GT from eddie - and knew that it was a bad rep.
The bartender later noticed my GT and nodded with a kind of knowing glance as if he knew that the guy had a fake and mine was real!
I got a kick out of that and never uttered a word to the bartender or the other guy.