My understanding — which mostly comes from reading about the "scam centers" operating in the Laos "golden triangle" autonomous region specifically — is that everything happening there is either "legal" or "unprosecutable" due to jurisdictional problems. If a Chinese-owned-and-operated company has a bunch of illegal immigrants from Myanmar and Thailand and Cambodia (but no Laotians!) locked up in a "scam center" in a Laotian AR... then which police force has both the motivation and the right to come knocking,
without that being an international incident and potential incitement to another territorial war in the region that nobody wants?
Laotian police have been quoted as saying that they have full authority to come into the autonomous region to investigate a crime, given irrefutable evidence of a crime — but that they can't come in without such evidence; and that it's very hard for them to get such evidence.
I'm guessing that by "crime", here, they probably mean "a felony" (or whatever the Laotian equivalent is) — which is likely the blocker for them, and probably the basis for the very thin line that these criminal gangs are treading.
I believe that "an escapee who can show that their organs had been harvested" would be irrefutable evidence, enough for a police raid; while "an escapee who told a story about being held captive for years" would not.
(And re: the other part, of some of the things happening there being "legal" — a large part of how these companies work is by indentured servitude, in the literal sense: they get people coming there to sign contracts for provision of services and equipment, that create a debt owed by the worker to the service/equipment-provider; and then they don't let them leave until they work it off. These contracts seem to have a lot of power for the gangs; they don't bother to chase escapees who haven't signed them, while considering people who have signed them to be "theirs to keep." Presumably, they've tested these contracts with local law-in-practice, and found that they actually work as a shield for what they're doing.)