A few issues with this. First, is that PayPal will only honor a case less than 45 days old.
Someone with the intent to scam will stall the deal long enough for this to expire.
The other thing to beware of are sellers that request you send the money "Friends and Family" to avoid the fees. When you go this route, you have zero recourse through PayPal.
One other thing...never accept an E Check as a refund on any deal that is closing in on the 45 day mark.
E Checks take several days to clear. If it bounces outside that 45 day limit, your clock has run out, and its over.