At Lowe's and they had to crack down on this due to a new(ish) Florida law. Can't work more than 6 hours of an 8 hour shift without a break. If I took a late lunch, of my own accord, they would get dinged for "forcing" me to work too long. Fair enough.
Yet another reason I love working for salary. So much less bullshit, so much more flexibility. If I want to knock off a couple hours early, go kayaking, work in the evening to run updates, fine.