Since you ask....
Let's imagine you are an Italian and you incorporate a
Delaware company. If you open a business
bank account for your delaware company in a bank that is Fatca compliant, they will report the balance of this business bank account to the
IRS. Then, wherever you live in the world, the IRS will send you a letter to ask you to pay income/
corporate taxes for US derived income. If you don't pay they will try to withdraw money from your El salvador account, and here it is a bit vague because it didn't happen yet as FATCA is pretty young. In fact, according to the IRS procedure, they always try to get penalties first. In fact, the penalties are so high after 1 year it is like they would seize your bank account.
FATCA is only reporting, then for law enforcement there is INTERPOL. Anyways, the IRS thanks to Fatca would identity the ultimate beneficial owner (the Italian person), so they would create an interpol notice to get the person in Italy. But then, in Interpol, it is active for criminals who have done something really bad to take into account. The offense has to exist in the Italian law & it should be something that is serious enough to require 2 years time in prison. The notice may be discarded because of that.
Anyways, ultimately they will wind up the US would strike off the Delaware company. I guess also this Italian person would be on the blacklist to visit the USA.
Also, the beneficial owner will have plenty of time to withdraw all the money from the business bank account if he wants after he received the letter from the IRS. He can pay the tax and wind off the company quickly.