I don't get why this keeps happening. I can only assume it's some broken database/system that isn't able to internally concretely express "this person is safe"

I don't get why this keeps happening. I can only assume it's some broken database/system that isn't able to internally concretely express "this person is safe". I'm imagining lots of conflicting signals, maybe from multiple systems that don't interact with each other. Given the US travel system's reputation, I can't help but think some of the problem has to be because of utterly broken computer infrastructure. Said reputation certainly can't help make the environment seem attractive to would-be techs trying to avoid potentially-soul-crushing job positions/environments. So the people that are left probably have all the innovation and inspiration worked/drained out of them (which sort of segues into an interesting fulfilling prophecy of a kind). Without the necessary infra in place, my guess is that agents' responsibility is much higher than is let on, and the go/no-go decision is probably a lot more ad-hoc than everyone is comfortable with admitting. That could reasonably explain all the inconsistencies... FWIW, I'm in Australia and have never traveled, so I don't honestly know.