My employer does this, and is the only one in town who does. It isn't deducted from our 4 week of vacation either. Its the only reason I stick around despite subpar pay.
It turns out the HR books are right and pay isn't the primary consideration after a certain point. The problem is that most HR people take that and say, "We're already soooo generous, we already offer unlimited vacation (lol), so we don't have to pay people too!"
I offered unlimited vacation in every business I started or ran since 1989.
But the abusive bullshit many companies have pulled while claiming “unlimited vacation” has justifiably made people cynical. This stated policy has become a warning sign instead of a benefit.
So in my new company we have a written policy four weeks but there is no way to track it (where the law permits this). sigh
Once you have a full time employee who is "the HR person" who has a department to run, and has OKRs, unless there is absolutely stellar company culture pushing for the contrary, that's it, that's the end, all your good benefits are going to get micromanaged away.
It turns out the HR books are right and pay isn't the primary consideration after a certain point. The problem is that most HR people take that and say, "We're already soooo generous, we already offer unlimited vacation (lol), so we don't have to pay people too!"