Presumably given they’ve all been released in the past few years and are still getting updates the manufacturers would release an update disabling the functionality to comply with law. Same with end user devices removing the functionality via software update.
You’d have a small percentage of holdouts who have auto updates off and also refuse to apply it manually and who also have non-updated computers or smartphone. They’d leave it up to whoever buys the spectrum to locate illegal use like this based on detected interference in their usage, report it to the FCC and they send you a nasty letter followed by debilitating fines and a legal order to seize your equipment if that fails.
In practice people who go out of their way to avoid the updates that disable it will probably see no consequences but decreasing benefits as well and will eventually update or replace devices.
Kids whose schools set up their chrome books inadequately and who found a way around the strict controls to watch porn.