Speaking from experience, compensation has absolutely nothing to do with it. In an "AT WILL" employment environment, they can and will fire you if you piss them off. Either that or they'll withhold raises/promotions/bonuses, or just blacklist you from the cool stuff.
I was once reporting directly to a Vice President. I asked to have a BlackBerry because I wanted to make sure I could keep on top of emails. Not that I would answer them, but just so I know how to plan every day in advance. It got to the point where even at 1am we (myself and the three managers who reported to her as well) would get calls from her about stuff that needed to be done. She never stopped. I was out of town on training and every evening they would take the trainees out to events, I remember one time I went and left the BB at the hotel, boy...I never heard the end of it.
Some companies have a work culture way worse than anything I would eveyr propose. The word "tether" wasn't originated by the cell carriers, it was originated from the overwork companies, as in being tethered to the job, and if you don't reply, you'll get fire(d).
I was salaried too, so that made it even worse. Had I been hourly, my overtime would have easily doubled my income. We were working on Christmas F'n Day, Christmas F'n Eve, New Years F'n Day and New Years F'n Eve, PLUS the weekend between them.