I think that was a comment on your blog ! I bookmarked the comment as it was the first time I heard about this too. It was here : http://spencerfry.com/whats-a-non-programmer-to-do

The problem with that logic is they can also withdraw from it.

Use their debit card (or snail mail check) to withdraw, close your bank account tied to PayPal if possible, they will overdraft you someday and cause you as much hassle as closing the account now.

It's called Autosweep and you need to call up to enable it as far as I'm aware. It's not possible to activate on the site alone. I'm not sure if it also authorizes them withdrawing from your account or not.