You could tie it to your ticket like a punch card. When the bar does the standard Id check they’d also check your boarding pass and check if the name is the same then mark it / digitally update it. Even if they don’t do a limit at the airport it would still be good to let the attendants on the flight know “alright this guy’s already had 5 beers, don’t serve him anything on the flight”
It is a different level of scale, mastodon has about 1 million users spread over a bunch of instances. Threads has over 200 million users on one instance. also due to the network nature of social media the amount of connections and messages sent through those connections can scale exponentially with the amount of users.