> It seems to me then the owners of the offending equipment are responsible for the bill. I don't see how you can come to any other logical conclusion.

Because at the time the equipment was bought, it met every applicable federal standard. This would be unfair to the owners who had no way of knowing about the issue.

Also, in nearly every other case I can think of when spectrum changes, the FCC grandfathers in owners of legacy equipment.

> At least I know why cell service at the airport is awful.

I don't think that's at all related, given that we just started rolling out 5G. Plus the bands in question don't travel through walls very well. :/