As a graduate student, I feel that (at least within my research group) there is this "unlimited time off" policy, but in the end it's not really taken advantage of very much and it certainly doesn't take any stress away from work. Even this holiday season, I'll be taking a week off from work, and I always phrase it as "I promised my mother I'd be home for at least a week".

The minimum vacation policy sounds like an interesting alternative, but I'm not sure it could fit within the academic community. Any professor has the power to instate such a policy, but at any given moment there's an "important" project that rests on one or two people working hard to get results. Often, in academia, you have those people that are precisely the kind that will work hard and get shit done, and honestly I can't imagine there being an understanding of "minimum time off". It's more convenient to the professor and the ambitious PhD student/post-doc to have the "take time off when you want" policy, and let the unwritten rules and undertones dictate when you should take time off (e.g., when you just finish a project).

I know the article wasn't trying to apply things to academia, I just thought I would consider it in that light.