Some cop noticed the beer, most likely - and they were one of the good guys.
Another one might have taken this opportunity to start an in-depth "investigation" (read "bullying spree") to figure out who sold the beer and who bought it and passed it on (if anyone in that bunch might plausibly have been underage.)
Another one might have taken this opportunity to start an in-depth "investigation" (read "bullying spree") to figure out who sold the beer and who bought it and passed it on (if anyone in that bunch might plausibly have been underage.)