Days in lieu, from working OT on salary.... IMO, is required.

I don't work for free; if you're paying me to be present for specific hours, regardless if it's salary or not, then I expect to work during those hours and not any other time.

If, as a salary employee, I'm paid for results and as long as I meet my deadlines (and deadlines are reasonable) I can work whenever, then yeah, I'll probably put in unpaid OT sometimes. I'll tell you something though.... With my level of experience, it would be unusual for anything to take so long that it requires that I work more than what is typical.