The "97.3%" match is probably just the confidence value - I don't think a frequentist interpretation makes sense for this. I'm not an expert in face recognition, but these systems are very accurate, typically like >99.5% accuracy with most of the errors coming from recall rather than precision. They're also not _that_ expensive. Real-time detection on embedded devices has been possible for around a decade and costs for high quality detection have come down a lot in recent years.

Still, you're right that at those scales these systems will invariably slip once in a while and it's scary to think that this might enough to be considered a criminal, especially because people often treat these systems as infallible.