It turns out that the current implementation has a serious bug, so at the moment the answer is no, it doesn't. But the situation appears to be salvageable.
> If this works then why did people both writing all those posts about hygiene?
Well, this is (a form of) hygiene. But it's not complete. As others have observed, it doesn't work for macros (though once the bug is fixed it will) and you still have to put in gensyms (a.k.a. uniqs) manually to avoid downward capture.
