Lots of things would have been built but if there were never any established standards put on things, it would be pretty scary. A lot of things are designed and built and go through extensive testing to make sure they are safe. Lots of things have required beefing up or a redesign because in actual use there were failures. That's why vehicles have recalls. I mentioned trailers because there are some really poorly built ones on the road that shouldn't be. A visual inspection by a vehicle inspection station would reveal poor welds and too light of construction. Wouldn't be hard to find someone to do that. New Miller and Lincoln trailers for welders that go on the highway have to be inspected by a 3rd party when brought into Canada before they can be registered. A large semi trailer manufacturer up here was forced into receivership because several of their largest trailers were failing. It was a result of poor engineering. Even engineered stuff can fail. Imagine if there were no inspections or certifications for lifting apparatus or cranes didn't have load charts. If something is built just for use at home or in a shop is one thing but inspections should be required on some home and shop built items that could pose a serious threat to others should they fail, like trailers. UL, CE and CSA test and certify all kinds of things. There are other agencies that certify things like ROPS structures for equipment. It costs a lot of money but it sure gives piece of mind in the event of a rollover.