To be fair, it would be a pretty low-key drinking problem, since this belt buckle flask can only hold two ounces of booze (about a shot and a half), but it's still a strange message to send the world. If you tuck in your shirt, exposing the device, you're saying: "Hey look, I appreciate dressing neatly but also advertising the fact that I need to have alcohol attached to my person at all times."
That's still better, though, than not tucking in your shirt at all, and then stretching, or doing a cartwheel, exposing the hidden flask. That just says: "I have a drinking problem, and I would like to keep it hidden, but, unfortunately, I am an idiot."
You can buy this gem at KegWorks.
[KegWorks via Laughing Squid]