It is the moron DL Connection flight crews still living in the naughties...

I forgot from where I was flying...DTW I think...but the only time I have heard the 30-minute rule is when I'm on a commuter aircraft...clearly those are the best to overtake anyway, right? I fly JFK-DCA a lot and there is never boo about anything...you are barely in the air 30 minutes anyway. Maybe no beverage service in coach, but everyone is free to move about their cabin.

Actually on the flight from DTW they actually locked the forward lav door and everyone had to use the rear lav "for security reasons" / DCA. They don't do that JFK-DCA.

It's akin to the no phone mode/PDA during flight thread. The commuter airlines seem to operate in their own world of rules.