Here's my tale with pics and analysis of the leaking issue:
https://www.ninjette.org/forums/showthread.php?t=44054
On the 08, with its vacuum-operated petcock, a leak won't dump gas all over your garage, nor will it fill the crankcase with fuel. There's no affect on bike operation....
... IF your float seals are in good shape. Gas flows out of the tank into the bowls, floats rise until they seal the fuel line. Gas gets drawn out of the bowls by engine operation, floats fall, gas flows. Simple. If the float seals leak AND the petcock won't shut off, well, then you really do have a problem.
It's also an issue if you have to take your tank off for some reason. Then it's a Bad Thing. But for normal riding around, nah.
So basically the leak just disables a safety feature, namely the automatic shutoff at the valve when the engine stops running.
I only discovered it when I tried to drain the bowls for winter storage. Naturally, fuel just kept flowing and flowing....
I replaced mine, because the teflon bit was shredded. Also, the black rubber gasket is SUPER flimsy.
Bottom line: Leaking fuel sucks. This is a basic safety issue. It will fail, even if you've McGyvered it. Recommend replacement.