But depending on the environment (and noting that this project is specifically targeted towards communities seeking last-resort communication), there's definitely still risk, even if there isn't a spectrum authority with any real policing powers.
For example (and I say this speculatively), if you're broadcasting encrypted radio traffic in a conflict zone, it could be hard to differentiate between civilian traffic and military traffic happening on civilian bands, so you might be wrongly targeted by a drone strike.
If you already have a target on your back, radio laws can still be arbitrarily applied upon oneself, as in the case of Aung San Suu Kyi, who was once detained on the pretense of illegally importing handheld radios. [1]
[1]: https://apnews.com/article/aung-san-suu-kyi-myanmar-asia-ap-...
However, the buck stops exactly there. It becomes the landlords issue, not the tenant who might be operating the radio, where the property owner is liable to be fined if they themselves don't shut the signal off after a certain amount of time. I would guess the FCC lacks the sensitivity to target the signal to a specific unit in a given building in order to issue the fine directly to the involved individual.
I guess the lesson is you can do whatever you like as long as you have the actual radio mast on someone else's property as they will get the fire if the FCC bothers to show up.
Makes me wonder about those old FM radio dongles we had for cars that lacked aux jacks or tape decks if those would technically be pirate radio. You'd have to set them to whatever open channel was locally available and they had actually pretty good range; I remember picking up my friends signal while I was driving behind them.
1. https://www.insideradio.com/free/pirate-radio-crackdown-puts...
No. These generally are type-rated and carry a general license to transmit, their power is extremely low and unlikely to be a nuisance to others for that reason.
In my experience, enforcement of the rules is unheard of.
I did it after my friend tuned into AM radio for the first time and heard all the far-right radio and I said "hold my beer".
In the UK, nothing. There are far more important laws to enforce.
You will get some fat whiny old guy bitching about it to anyone who will listen, but you literally could not pay Ofcom to take an interest, and there are only about two people in the whole of the UK who have the skill to do anything about it.
Then again, as you say, they probably have much better things to do. Would be nice to hear more stations popping up on MW too as all the legit stations leave the band.
If you're not actively pissing someone off, it is unlikely anyone will bother you.
No-one is going to give a shit about you running unattended digi modes on 80m except some guy who wants the exact same 3kHz out of 300kHz that you are using to moan about his sore feet to his pal across town.
GMDSS is considered Pretty Fucking Important, and messing with it will attract the attention of the Coastguard, who have the legal right to make even the Diplomatic Corps miserable.
Let me put it this way - when a defective navigation light ballast at a US-operated naval base on the Clyde was jamming 156.8MHz for about a ten mile radius, absolutely obliterating the distress and calling channel, Ofcom got involved, passed their findings onto the estuary radio control office, the RNLI, and the Coastguard, who had all been reporting an issue, and "gave advice" on further enforcement they could carry out. Within half an hour the nav light was shut down, after a phone call where the Coastguard explained that there were some very angry people on their way with a radio engineer who was about to put a Stihl saw through their fence and shut it off himself.
They were on that thing within the hour, replacing the lamp assembly and phoned estuary control before firing it back up, and peace returned to Channel 16.
My sense is that at most you will be yelled at by HAMs - unless you are actually disrupting emergency communications. Ensuring radios can be used in emergencies is why licensing exists at all and people take ensuring it can be used for that pretty seriously (for good reason).