Indeed. Not a lot of people are interested enough to experiment with radio transmission and fortunately the ones who are tend to be keen hobbyists who understan

Indeed. Not a lot of people are interested enough to experiment with radio transmission and fortunately the ones who are tend to be keen hobbyists who understand how the systems work and take care not to break things for everyone else. The kinds of outage that can be caused by rogue transmitters are rare. Often it's a hardware failure that is to blame when they do happen. Hardware failures are also rare but when you might have millions of transmitters within a small city, sometimes you discover that rare is not the same as never! There is always the possibility of malicious or negligent interference if an operator has the ability to modify their transmitter's behaviour sufficiently though. I would personally be OK with limiting the sale or use of equipment with those capabilities to only people who have shown they are competent, for much the same reasons that I am personally OK with restricting the use of cars to people who have passed a test. It obviously doesn't prevent all failures but it certainly lowers the risk of failures that could endanger many other people.