You are correct, most tunnels have 'leaky-pipe' antennas connected to mini cell stations. But when you get a Federal License for one, you agree to the ITU treaties.
Federal law trumps in this case, localities can't do this without permission from the FCC.
Clearly interstate commerce, the way I read the Constitution. And I'm not a fan of how the IC clause has been abused.
/johnny
“But when you get a Federal License for one, you agree to the ITU treaties.”
Oh - thanks! So not quite the same as if I turn off my unprotected WI-FI and my neighbor using it gets mad.