But on the other hand it's been used for audio for so long that the world is saturated with transmission equipment. I think I'll become a pirate radio band as soon as public stations stop transmitting. Of course you can police that but the 80s showed that it wasn't very effective. It's just too easy to build one with a few components.
Also there's often going to be a lot of interference from abroad, 100Mhz signals while VHF can carry far under the right conditions.
Any new systems will be digital, and I doubt they are that sensitive to highly localized interference. If the interference isn't highly localized the FCC will rapidly perform an operator attitude adjustment.
All the pirate stations back in the day were ultra high power AM stations operating out of Mexico.
Also there's often going to be a lot of interference from abroad, 100Mhz signals while VHF can carry far under the right conditions.