Aside from all the BS PayPal pulls (which you can find elsewhere), it would all be forgiven IF PayPal would not support the chargeback. If an exchange can receives PPUSD, that person can buy Bitcoin, and then they could yell at PayPal that the charge was fraudulent and presto: you've got your USD back and you have your newly found Bitcoin. Exchanges would die very shortly if this occurred often, which it does, as you can see on the newbies board, with people getting scammed left and right.
Wow. That's outrageous. Are there any sites that support a withdrawl straight from the bank? (Other than MTGox, which is down)
As a side note, I looked at BitInstant, and it would only let me pay to MtGox. I thought you were supposed to be able to pay to any exchange? (like BTC-e)