With regards to alcohol, I have found in general if you treat people like children they will act like children. Treat them like adults and they will generally act appropriately. Matson’s and APL’s approach (as far as US Flag vessels) makes the most sense IMO. Anything else invites problems.
I respectfully disagree @CaptTimD. Current rules, i.e., CFR’s do not prohibit alcohol onboard ships. It does put strict parameters on its consumption. Maersk’s policy on US Flag ships prohibit alcohol aboard ships but I do not believe that is the case globally.
The policy, rightly or wrongly, is viewed much like Prohibition was back in the 1920’s.