That's a might thick hat you are talking through and you make huge assumptions:

the disclaimer will be ineffective - your disclaimer cannot trump the law

If that were the case, Australia Post wouldn't be able to get away with not providing guaranteed delivery for every item that they take legal responsibility for.

Kinda like setting up a posh restaurant in Queens.....pay the tracking or find something else to sell as it may not be a feasible item for online trading

Are you a Yank? I'm not setting up a posh restaurant in Queens or any other part of that contemptible country. I am not in and have no wish to be in a business where profit is everything. Neither do I want to/or will accept responsibillity for items I have duly entrusted to Australia Post. In Australia, only "proof of posting" is required to absolve a seller of liability and a photo of a stamped, addressed and sealed parcel, large letter or whatever should be enough. In fact, Paypal indicated it was (actually their suggestion) when I had an issue with a thieving buyer a few months ago. 

I just sell a few items I no longer want, to recoup some funds to prop up my pension so it is never going to be "find another product" and is hardly in my perview to do anything else. I think it insulting that YOU suggest I do, just as it is insulting that it should be intimated that I or anybody else should go elsewhere if I don't like it, which seems to be your crony PJ's stock in trade. Neither the OP nor I have broken any eBay rule or any law for that matter. Who made you the "eBay police"?

para 2 - hmmmm perhaps there was nothing in the envelope when they paid, perhaps the contents weren't as decribed so the seller didn't want to risk a neg or a chargebackand decided to blame aus post instead, or maybe, they just forgot to post it after paying, we often hear of people walking out of supermarkets with something tucked under their arm even though they went through checkout and paid for other stuff. Maybe they got distracted, or had a heart attack between payment and putting it in the letter box. dunno, but there are a few possibilities.

Gee, you are really are clutching at straws now. They went to the post office to buy postage for an empty envelope or they were planning a massive fraud that would support them for the rest of their lives, all on a $5.00 to $10.00 item. No wait, they had a heart attack and died and the OP is a disembodied spirit with an axe to grind. Unbelievable!!

risking reputations? PayPal doesn't know if you are a scammer doing this a million times or a genuine person

While I won't be defrauded by some cheaparsed buyer who won't take responsibility for their own inactions, I care that my many honest customers believe me to be the honest person I am. Other than acknowleging that I follow their rules, I don't give a tinker's curse what Paypal thinks of me.