system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What happens to the debt if debtor leaves the country?

Here is a situation:

A foreign citizen temporary moves to the US for studying, job contract, etc. 
In a couple years he has a debt, say $50-100k (credit cards, medical bills, student loan...).
Then, he moves to another country and never bothers to pay off the debt or declare bankrupcy.

Are the creditors able to collect his debt somehow or sue him abroad? 
Are there any related international treaties?

Will he ever be able to get a visa and visit the US again?

Is the credit worthiness information shared between countries? 
Can a foreign bank (i.e. Canadian) access a US credit report?

Is there any difference if the debtor is a US citizen?

What about other countries? I.e., if someone has a debt in, say, Germany and moves to another EU country?
gpt
Essentially, they "get away" with it. But ask yourself this; unless you're already super established and have a tone of stuff lying around that proves that you can either pay back the loan or the bank will take your shit, you're not going to get a massive loan (like 10 million dollars or something) that will really be worth completely and totally skipping your established life in the country for. If you're just some random asshole, you're gonna get like 10,000 bucks, *max*, if you're in good standing so far. Is that really worth skipping a country for? Because if you ever go back there, prepare to pay.

**Summary Edit:** if you have a huge debt worth leaving a country forever for, then you probably have assets that the bank can seize. If you don't, then you're going to become a very, very poor man whenever you plan on returning to that country.