- Very free movement between regions.
- No norm of distrust for strangers. In a traditional society, when someone new shows up, the default is that nobody trusts them to do anything. Any transaction that doesn't settle immediately can't be done, etc. But modern people are supposed to treat strangers as if they didn't just show up because they got ejected from their home. This means exiling people more or less corresponds to screwing over the hapless, trusting society they get exiled to.
There is a solution implemented in the US, the sex offender registry, meant to address this exact problem. ("What if someone enters our community, but they're not trustworthy?") The problem is that the formalization of the sex offender registry (1) is the same everywhere -- not a big problem; the old norm of distrust for strangers doesn't differ in that regard -- and (2) supersedes the old system whereby a stranger could, over time, become trusted. You might personally trust someone who once urinated in public, but he'll never be officially trustworthy no matter what happens.
There are no hapless, trusting societies any longer. The way the criminal justice system works, if we exile these guys running the vaccine scam, the nations we exile them to will immediately deport them back to the US. No one wants the criminals from other nations. So unless your crime is not terribly serious, exile won't work.
It certainly won't work in this instance. This is not some trifling misdemeanor.
We're talking about someone getting kicked out of Phoenix and moving to Austin.
https://www.digitalpanopticon.org/Convicts_and_the_Colonisat...
The big question is how do you implement such a thing? I think the English had the right idea by expelling them though I don't know if such a thing would still work in 2021...