I was in a position last year where theoretically anyone could ask for any time off, but most people didn't, and most you got a bunch of hemming and hawing if it was a known busy time for the company.
What ended up happening is everyone ended up disliking the guy who took the most vacation, as they were not supposed to take it at the same time(at least not 3 at once), and he asked first. It was ridiculous, IMO. I was vocal about how you shouldn't hate the player, but hate the game, but older guys used to not taking much vacation thought people should limit themselves a couple of weeks. Eventually guy who took the vacation was fired! because most of the crew didn't like him and didn't like working with him. I'm going to take twice as much as him this year and see how it goes.