At one place I worked, they were wanting on-call shifts of 12 hours being no more than 15 minutes away from being logged on (it was a multi-week Big Event) with

At one place I worked, they were wanting on-call shifts of 12 hours being no more than 15 minutes away from being logged on (it was a multi-week Big Event) with the promise of, maybe, time off in lieu as recompense. They were most displeased when I declined this opportunity.