Paypal also asks for your bank username and password for instant verification. The process looks identical to the one displayed here so I would imagine that is where this came from.

I'm not saying I would trust giving my bank details out in general, especially with these bitcoin businesses, but I have to say that when I wanted to open a business account with paypal and I was faced with either waiting days or instant verification, I took the instant option even while knowing it was probably a bad idea.