Having worked with many people who have used bands for a short time they were not authorized to and never ended up on the FCC shitlist, I would be okay with a very low power, temporary setup to play with/test something in the GAA band because it’s kind of a free-for-all among those who have a license to this spectrum anyway and being low power means you won’t be interfering with much, if anything.
The FCC tends to go after transmitters who are actually disrupting communication and if your signal drops off to the point where ambient noise on the band is louder outside the permitter of your house, you’re not going to get that knock on your door.
If you think that's bad just wait until you hear what an FCC band license costs.