When I taught newhire f/as I always said there were 4 things (S's) that could get your fired on an airplane.
1. Sipping 2. Smoking 3. Stealing 4.SLEEPING (unless you are really fast and when caught look up and say
"Oh, I didn't know we were forbidden to pray these days"...If you're that "good", have at it.
Pilots and f/as have crew rest built into contractual language on certain Intn. flights. But they would certainly be at job risk if they
got caught sleeping on a domestic flight or shorter Intn. flight. I flew all nighters for a good portion of my career and there were times that it was very difficult not to do the head bob. There were many world problems solved on those flights.
As for turning someone in.... It is more "appropriate" to go to your union steward or local rep and handle it through professional standards.