We work on accrued leave time here (it's legislative in Australia anyway). But even so, we do let people take a bit in advance or even without pay if they are an employee in good standing.
I just can't imagine any company ever thinking a person was just going to skip their already booked vacation because of work? What kind of power trip are they on! I do remember a US friend of mine having a similar situation where her boss told her they needed her to stay and work at a time where her honeymoon was booked for, which had been approved ages beforehand. She laughed and said absolutely no way, and they backed down. She too would have quit if they'd pushed it. I wonder if it's because holidays aren't a legal thing over there but often an employee benefit bestowed by the company, so there isn't that same expectation of people being able to use it, more of a "we giveth and we taketh away" type mindset by bosses. (We do have some discretion here, for example we can insist people take it during quiet periods or if they accrue too much, but it's fairly rare to decline a request! I've never in my whole career had a vacation request declined, and I use all of my leave each year). And re waiting for approval, usually we do the opposite here. I'll say to my boss "I'm thinking of taking X amount of time off in X month for X reason, will that be ok?" they say yes, I book flights etc, and then I submit the formal request knowing it will be approved.