Re: And how exactly
"therefore your US bank account(s) and other assets are frozen until such sum is paid in full", etc., etc."
It goes further than that. Banks that participate in the SWIFT system or do business with the US so they can shift US currency have to comply with US court rulings. Many banks outside of the US will not open an account for a US citizen due to the hassle of complying with US banking laws. That really sucks since if you travel a fair amount, it's handy to open a bank account to have local access to funds without getting nailed with fees by using a card that may or may not work when you need it. Having a local account also makes it easy to deal with any problems. The toll-free number on the back of a credit card doesn't work in most other countries.