Paypal is just an intermediary between merchants and whatever payment methods customers use to pay Paypal, such as debit/credit cards and bank transfers. And guess what? The modern financial system has no irreversible payment methods. Bank transfers, credit cards, and ACH are all reversible, wherever you go around the world.

If you haven't heard of it before, the May Scale of Monetary Hardness is a great way of thinking about this: http://stakeventures.com/articles/2012/03/07/the-may-scale-o... . If you're a payment intermediary, and you're delivering irreversible assets like gold coins or briefcases full of cash in exchange for very reversible payment methods like credit cards for personal checks, you will get horribly, horribly burnt by fraud, because you can deliver the gold coin and find out weeks later that your credit card was charged back. http://whatilearnedtoday.jameslarisch.com/?action=view&url=b... is a great example of this with Bitcoin and Paypal respectively.

It's not even about educating the user about irreversible transactions -- it's just that there's no way for Paypal to offer them unless customers fund their Paypal purchases by dropping off briefcases of cash and gold bullion at their local Paypal branch.