IANAA, but... Remember that these vacation policies also offer a very significant accounting benefit compared to PTO polices that let employees accrue & bank PTO. The accounting downside for these PTO policies is that many employees end up with huge PTO balances (lame for other reasons) that they build up in advance of leaving the company. Because the company must pay out in cash the whole PTO balance when the employee leaves, the company actually has to keep (often very significant amounts of) cash on hand in proportion to the collective banked PTO amounts. This is lame and it's avoided in "you get 0 but take as much as you want" scenarios.
> Because the company must pay out in cash the whole PTO balance when the employee leaves, the company actually has to keep (often very significant amounts of) cash on hand in proportion to the collective banked PTO amounts.
Depends on the state. Many states let the employer decide if they want to have a pay out policy or a "use it or lose it" policy.