At my job we're expected to at least try to be available if needed after hours which in my 3 years here has happened once and it took about 30 minute and I waited until my son went to bed for the night.

In return we get to leave for doctors appointments, picking up kids, errands etc without having to use PTO or make up the time. It's a pretty sweet deal for the developers and no one abuses it to much.

At my old job they tried to get us to work after hours pretty frequently for a fraction of what our hourly rate was, we were salaried but when you broke it down you'd be getting like $20 an hour instead of $50. Ridiculous and almost no one did it.