What are the probable consequences, short and long-term, of doing this?
I don't expect that this is advisable, but does anyone actually know if the government will come after you if you move to say, Thailand to escape your debt to the government?
Debt collectors will continue to attempt to find you. Eventually, if you hide well enough, they'll stop.
That said, I do know that your credit rating in one country is not currently linked to your credit rating in another. For example, it's possible to have sterling credit in America and abysmal credit in Canada.
However, the issue in your original country doesn't go away. It may stop impacting your credit, and the debt collectors may write it off and stop pursuing it, but the debt is never cancelled.
> but getting back into the US could be sticky to say the least
Really? They're not going to allow you back into the USA, or arrest you at the border for defaulting on a loan? That doesn't sound very credible at all. Any evidence to back that up?
Well, it depends on how far you go in the attempt to get out from under this debt. Remember that student loans in default can be funded by automatic garnishment of income tax refunds, and if you are abroad and haven't kept your income tax reporting up to scratch then you might be exposing yourself to charges of tax evasion. An extreme scenario I agree (albeit less so for non-citizens), but at the very least your credit will be hosed and re-establishing a financial life in the US would hard.
Defaulting on student loans is a civil debt. Filing fraudulent tax returns is a crime. I have never heard of someone being extradited or having their passport cancelled for defaulting on a civil debt (probably because governments have no direct interest in civil debts per se)
But student loan debt is almost entirely held by the federal government now. Does this mean it's still civil debt? I'm inclined to think that it isn't.