Wealth doesn't defend itself though, and a bunch of rich guys might think they're slick but even a rag-tag pontoon of somali pirates is going to have more battle experience: so you'd have to hire a small mercenary force to guard the place. How much will you pay them? What's stopping them from killing you and taking the place over for themselves?
I can't see how paying taxes is the biggest driving force for this idea. I think these people want the freedom and power of an aristotelian-scale democracy without dealing with the majority of idiots that affect our lives every day.
Agreed. But there is what should be done, and what is done. I don't think this is anyway admirable, or of any benefit to society, (it's basically taking wealth harvested within a system out of that system) but I do see that it might be a possible solution for a perceived problem that exists for very wealthy individuals.
In any case, despite the ridiculousness of the idea, this shows that the current sovereign-state compartmentalization of the earth is no longer the best way to run it and we need worldwide cooperation to both fight tax evasion and allow greater mobility of people and goods. Isolating the rich from the masses is only a good idea in the sense that it ends in an explosive way, like the french and bolshevik revolution.