smudgie - perhaps I could have worded my last post a little better - didn't mean to wind you up.
Because passengers are paying rather than being paid for the duration of a flight, there will be an expectation that passengers have a greater degree of freedom in what they do compared to crew. An example being able to snooze whenever they like - whereas crew are generally encouraged to be awake for the duration of the time the aluminium tube is in the air.
Many airline marketing departments have in the past employed an advertising strategy which implicitly promises free alcohol to all passengers - the bit about 'we won't serve booze if we think you're drunk' has tended not be advertised at a pre-sales stage that much. Thus pax in all but the cheapest of seats have this expectation of getting free booze. I can't recall a safety demonstration ever saying 'Please try to stay sober enough that you would be able to use the emergency oxygen mask if you had to'
Yes, there are bounds beyond which passengers should not go. However, in my opinion, airlines also need to hold back a bit from using the offer of on-board alcohol as a marketing tool to sell tickets if drunkenness is viewed as a problem.