The difference is that banks can be governed through the country(s) in which they conduct transaction, and thus you can do something.
If paypal just decides to fuck you over because mr. no education lowcost/lowest bidder employee thinks you are doing somethign wrong - there is no phone call, no notification, no innocent before proven guilty. Your money is not yours until you suck them off good to pay them back.
Our credit card merchant accounts have normalized amounts attached to them. Meaning that the typical transaction through our business is 100-700 or something like that. If you strangely deviate from this, all you have to do is give them a call and let them know.
Naturally dotting your T's and crossing your I's is important :P, but with paypal they don't need just cause.
SA 4 Life!