There is nothing that says they have to give any time off on a daily basis. If I was working under such conditions, I would certainly want to be compensated for it. You have to read the fine print before you sign your life away..
In this case there was no fine print, but the boss was just on a power trip that day - I almost always got the weekend off, except for that one time. I think he was embarrassed that what I predicted happened. When I gave him the warning earlier I was told, "Don't worry about it. That's not your job." I reminded him of that when I griped.