We have an actual unlimited unpaid time off policy. I have several colleagues who have taken 6+ months off (even repeatedly). Obviously I suspect that wouldn't be well-received within the "unlimited" paid leave at Netflix (but perhaps I'm wrong, I just can't imagine it).

I quite like the unlimited unpaid policy, is there a reason it's rare? I'm guessing the implication that if you can take 6months off you weren't really necessary?