My worry with a mandatory one-week vacation every month is that people won't take the vacation - they'll use the time to make progress on features or other work

My worry with a mandatory one-week vacation every month is that people won't take the vacation - they'll use the time to make progress on features or other work-related projects. Burnout isn't solved by a simple "You must spend this time away from your keyboard and this time at your keyboard," and some of the most difficult burnout for me to work through has been when a problem has seized hold of my mind and I've felt compelled to keep working on evenings even when I clearly wasn't making progress. If you end up in a situation where the document on paper says everyone's taking time off to surf and paint and the actual practice is that some contributors are doing work during this time—and, almost certainly, not getting punished and in fact getting promoted for doing so (perhaps because they commit locally and rebase so nobody knows they were working during this time)—you're going to end up with way more frustration, burnout, and uncontrolled work schedules than you ever started with.