The problem is you need only 4 and not 10000 because Android Wallet and MultiBit connect to only 4 nodes. Someone who wants (and is technically skilled enough) to rip of people with fake nodes during large zero confirmation cash transactions (what a stupid example anyways, who on earth is doing large cash-for-bitcoin transactions with zero confirmation anyways?) can easily have 3 (or 7 or 11) friends in his gang with (anonymous!) passports to help him.

This idea is so ridiculous.

And on top of that the most dangerous and most likely enemy, the government itself, can easily fake 100,000s of passports.

Proof of work is done by miners, the problem does not exist in the frst place, thats why global consensus is established by the miners, thats what confirmations are meant for.