I've never seen an imposed limit in-flight in FC, even when I can smell the fumes coming off a passenger next to me after they had 3 or more. I have been told in the AS lounge at SEA when ordering a second beer that "that's the last one, OK?" after the bartender asked where I was flying to, SAN in that case. Admittedly, I drank the first beer relatively quickly, but still thought it odd.