The problem is, the guy got through the safety check, didn't throw up or fall down. What one person sees as slightly drunk another may see as not drunk at all. What does "twisted" mean anyway? Not found in Part 1 of 14 CFR. Of course I am obfuscating here but that is what lawyers do when the law is unenforceable. Legal ramifications at a trial after an accident aside, it is always at the pilots discretion for letting a passenger onboard. After all, the ship can't fly without a pilot. It is the word " obviously" that leaves the door opened to these kinds of things. A cop can't make up their own sobriety test, can't have everyone doing something differently. Pilot judgement is kind of like that. How long would the pilot last if they said two out of four people ticketed for the birthday flight, including the birthday boy can't fly because there is alcohol in his cologne and I think he might be drunk. I'm only making the excuses that a totally distraught and embarassed pilot might make to save a career.