Companies have "No Allocated" vacation (By no stretch of the imagination is it unlimited) - for exactly one reason - so they don't have to carry the pay-out lia

Companies have "No Allocated" vacation (By no stretch of the imagination is it unlimited) - for exactly one reason - so they don't have to carry the pay-out liability on their books. But, an ugly side effect, is because there is no allocation, there is also no forcing function for people to "use-it-or-lose-it" - which also means when you are in crunch-time (which defines every startup I've ever worked for in the first 4-5 years) - it effectively means no vacation, excepting Christmas, which still seems to be untouchable (so far).