At least in the US there is no legal requirements or standards for manned space flight. You need FAA approval to send up any rocket but they don't get a say on the cargo. NASA has acted as a defacto standard but Blue Origin are launching above the Karman line without any NASA checks.
Cars are regulated, it's entirely legal to build and drive a car you designed from scratch. You just need to get it inspected and make sure it conforms to the various rules.
The sub operator will be sued into extinction, and that's the proper way of dealing with this sort of billionaire tourism racket when it goes wrong. The next people to try to do something similar will need to get the sub tested to get any insurance cover. And so the invisible hand of the market adjusts after the horse has left the stable and catastrophically imploded.
Cars are regulated, it's entirely legal to build and drive a car you designed from scratch. You just need to get it inspected and make sure it conforms to the various rules.
The sub operator will be sued into extinction, and that's the proper way of dealing with this sort of billionaire tourism racket when it goes wrong. The next people to try to do something similar will need to get the sub tested to get any insurance cover. And so the invisible hand of the market adjusts after the horse has left the stable and catastrophically imploded.