I agree with everything you've said, but how do you feel about your phone ringing at 2am on a Sunday?

Is it reasonable to come in and do a few hours then, and just do a few less on Monday morning?

I personally am happy to work the odd late day, even stay late with the team, grab a pizza, etc.

Getting calls in the middle of the night, or on the weekend, or on a holiday is a completely different thing that requires compensation, no exceptions.