'You only have to provide proof of postage for Paypal'

Incorrect. If you've been lucky enough to catch a slacker at PayPal who'll accept a receipt and reject a claim purely on it, you should be buying a lotto ticket.

In my experience, they have requested proof of lodgement (receipt is not proof of lodgement - it needs to show the address of where you sent it and stamped by AP), and it needs to have proof of delivery (address including suburb etc - not the next suburb over, the LPO, the mail centre etc). It's a warm fuzzy if it's traceable in between. 

PayPal may tell you that they have had plenty of people send in receipts and they assess them on a 'case by case' basis but a) that is a pure grey area in their policy as it stands which they are entitled to reject and b) I don't enjoy grey areas when some dodgy scammer wants to play silly buggers.

I am sure many of you think some of us are being over-excitable and should just take our chances but for the time and effort we put in and the bias in the system, this is the very last way we have to protect ourselves and it's now in doubt. That's worth being worried about.