[staunch]

"It sounds great, in theory, but would be hard to implement."

There's nothing difficult about implementing it. Clearly your employer just doesn't buy the concept at all. They probably only offer 3 weeks (slightly higher than average) as a recruiting incentive, which is pretty dishonest if they don't actually let you use it.

The reasoning behind this concept is what's important. It's about treating employees as equal partners in a relationship, as opposed to children, like most employers do.

Definitely read this essay if you havent: http://paulgraham.com/opensource.html