Very true, but the operative word is "could". I am considered by many to be "big boned" and, on that ONE (and only) occasion mentioned, the 3 pints were imbibed during the course of a large meal plus sweet, and although it could be argued that I may have failed a breathalyser, the odds are that I wouldn't have. I take your point, however.
A few years ago, we played at Wolves and went to the Holdens Brewery tap for pre-match refreshments. The driver had bought a state of the art breathalyser for that very reason - it was more modern than the ones the police used at the time. Straight from the pub, my reading was amber, and after the match some 2 hours later, green'. That was with no food consumed.