If you doesn't go off duty at the same time, and it's unlikely that all the ones off duty at any one time are drinking to the point they're intoxicated.
Why do people take things so litrally?
I think you missed my point. To illistrate why synthahol is
better on a starship.
Yes I know not everyone is off duty and no not everyone at party will get drunk! But even if say a 1/8 of the crew were at a big parts and got pissed and a emergancy happend in which case everybody is called to stations imagine the fallout?
You also dont want to risk a vital officer succumbing or indulging in alcoholism which is a trap any human can fall into accidently. So best way to prevent that? Well try and have synthahol only on starships (though we know that rule is bent sometimes).
My point is synthahol is safer on a 4 million ton starship packed with weapons and sheilding whose purpose is to go into the unkown or defend the federation.
If I was in charge of starfleet command I would have a Zero tolarance of any serving personal keeping or comsuming alcoholic bevrages while stationed on a Starship or starbase. Its not that im against booze, being a brit I love a booze up. But when saftey is involved it has no place. I would have struck off the Enterprise A senoir staffs commssions for consumeing a Alcoholic bevrage which did infact impair there responses in TUDC.