Union rules cause double time (2x pay) to kick in at lower daily and weekly thesholds than at non union jobs.
Sitting in a cruiser playing candy crush counting as "work" is funny when you compare it to the fact that flight attendants only get paid for the time when the door is closed on a plane.
However, there are many jobs where you might be stuck at work. Being at work == getting paid. Thats not really that shocking of a thing. My wife's dad worked at a children's 'training school' (kid jail) and they often had lock downs or were legally required to have certain number of people on site for certain operations. So he might be there and simply couldn't leave, but might not be 'working'. He was paid for those hours, which I think is pretty reasonable.
The new ADAs were started working on the vast number of minor crimes that occur daily in NY that result in an arrest but that will almost certainly end up resolved with just a fine after a short (a few minutes often) bench trial.
The courts that handle these run 24 hours a day. The ADAs operate in shifts. He describes how when arriving for his shift he'd have to step over a large number of sleeping police officers in the hall.
The officers are there either to give a statement to the ADA or to give a statement in court when the case of the person they arrested comes up.
It can take many hours between arrest and an ADA starting to work on the case or it getting called in court so as soon as the officer finishes their regular work shift they come and wait at the ADAs office. That waiting time is on the clock and all overtime.
He would often arrive for a morning shift and there would be officers who had been waiting since the end of the day shift the day before, or longer, if I remember correctly.
Two or three of those in a week and an office could get a lot of overtime, most of it spent sleeping.