Fortunately, buses are not invisible and you can look for a bus before crossing a street to gauge and control your risk of being struck by one.

Sorry, that's a really poor analogy.

Because there's a handful of companies (lectronz, seeedstudio, ebay, etc) that have the full shipment lists. So the compliance agencies don't have to go after individual business records one business at a time; they can go to probably fewer than 10 businesses and find the suggested mass rule breaking with a sql join.

See also the national tax agencies with NACE codes (euro version of NAICS).

Umm akchully, not crossing a highway to avoid being hit is a perfectly sane course of action.