It takes as much practice as the indirect approach.
It works BEST in clubs, there seems to be a slightly more primal air to the place which lends itself well to powerful kino.
Gotta agree with whistleblower - it's less suspicious. She knows why you're there, what you're doing and what her options are.
And finally... regarding flakes. Yeah, if you do raw direct flash game she's not gonna be interested in seeing you again [Most likely]. But direct game where you throw in a few titbits to build comfort and a connection as well. There's no reason why you won't get a day2. There's plenty of time in direct to get all this stuff done anyway.

I believe you're only as strong as your weakest game. If you can never go direct then sooner or later this will kick you in the teeth. On the other hand if you can never be indirect then that'll damage your game just as much.