How many billions are in numbered Swiss accounts and off-shore havens?
You've been watching too many movies. Switzerland now shares all that information with the US:
http://web.archive.org/web/20080611115027/http://www.treas.gov/press/releases/kd3795.htmNot only that Swiss bank accounts were only popular among working class and not among the rich. Why? because if you are rich, you don't have to pay taxes.
Lets take Google as an example. I don't have any information on Google's "tax-evasion structure" in the US (however you can bet they have many tricks) however, outside of the US, Google is really called "Google Bermuda Unlimited", they are a company in Bermuda that doesn't have to publish any financials and has an office in Amsterdam (which has no employees and is a PO box), which is owned by Google Ireland in Dublin, where they have a datacenter that was pretty much paid for by the Irish government under a series of grants they got for "research".
The total amount of tax Google pays with this setup is only 2%! and they got a free datacenter. And it's completely legal, they didn't have to use any anonymity or off-shore bank accounts, just tactics and damn good lawyers who were able to convince tax authorities across the world that all of this makes total sense.
And don't forget the way taxes work is that you have to prove to them you don't owe more, they don't have to prove anything. The IRS will simply say "OK we think you made $1 million in Bitcoin that you didn't tell us about, prove you didn't or pay up".