Ok some points from a dealer...
I have burnt 3 or 4 PP accounts and lost plus 2K on disputes that should not have happened.
In every case it was a noob, so yes that is where the problem lies but for obvious reasons.
1. A not well know fact is that noobs make up close to 90% of dealers sales, so we simply cannot afford to screen them.
2. Most noobs come to the dealer with no board interaction at all, they do not know (nor care) the accepted method of sorting issues. If they don't get what they want they go to Paypal.
3. Then you have the noob who comes to these boards simply to run a scam, obviously there is no reasoning with these guys and PP makes it far to easy for them. Goods not as described it a very hard claim for a dealer to fight when he needs to cover the fact they are replica goods. If you do somehow win that one and the buyer comes back with goods are fake/replica PP can burn your account.
A little know fact (at least here in Oz) is that Paypal can be blocked from accessing your bank account, yes they will probably chuck a hissy fit and burn your account but if they are trying to get $1500 (which they tried with me) to pay back a scammer it is probably worth it.
Ken