Second important thing is if the transmitter is built well enough to where bystanders other devices are not interfered with. I've seen a cheap security system using wireless technology make a motorized wheelchair go berserk. The person was off loading onto a lift and the chair tried to lunge forward.
Next is another important issue. If everyone picks a frequency band they want mayhem is the result. I used to work in a nursing home in maintenance. Not the janitor the person who handled power outages, fires, etc. I carried a handheld radio and there was a base unit plus about a half dozen more hand helds. A Taxi service unlicensed to be on the air and in the wrong frequency assignment made it to where we could not communicate. The Taxi Service was running 100 watts plus in the 154MHZ range with the cars using 25 watts. Our handhelds were about .5 - 1 watt. My boss reported the company finally. Taxis had their own spectrum and the owner had picked up a second hand system and decided to install it without seeking technical advice.
The Pirate station in question here if running a 100 watts would have covered a very wide area. The lower the frequency the further the signal carries. That is why in rural area the 155 & 159 MHZ spectrum is used a lot in rural area. That is why in the 140 MHZ HAM Radio operators with even handheld radios can hit repeaters. I know of a case where a 12 year old kid with a hand held HAM in between to high mountains at the lowest point still managed to hit a repeater and contact Park Rangers to report a classmate had drowned.
Nope it's not a good idea at all in dealing with radio frequencies for everyone be allowed to do their own thing. Many good rules are there for very good reasons. Thus one of the reasons FCC requires a license for some things including installing, repairing, and in some cases operation.
Some pirates have interfered with aircraft radio. A pirate in Boston called Datz Hitz at 99.7 did (and also stepped on WCRB 99.5, a classical station broadcasting out of Andover MA)
and they got raided and shut down.