I hear you. This already happens, but the range of activities a govt is concerned about a visitor potentially engaging in vastly exceeds what an AirBNB host is

I hear you. This already happens, but the range of activities a govt is concerned about a visitor potentially engaging in vastly exceeds what an AirBNB host is concerned about. The AirBNB host doesn't really care if you're coming into the country to perform what the country considers to be illegal or illicit activities, just that you don't mess up their property, and that you pay the bill (which is mostly handled by AirBNB). Govts have all sorts of considerations and filters through which visitor applications are considered, both positive (money they're going to spend) and negative (illicit activities they may be partaking in). In terms of reputation systems, most govts have rules around what data their operational agencies are allowed to collect and maintain that are far (far) more stringent than rules that commercial entities are allowed to collect and maintain. So govt agencies have contracts to use certain commercial systems as reputation meters. Don't think AirBNB is one of these. They are not a comparatively useful data aggregator, except of course for law enforcement trying to locate an individual of interest.