[markrages]

In the 90s I worked for a company in Kansas City designing pagers. We rented space underground for RF testing. There are no radio signals in the caves, at least back then. I'm sure that's different now, especially with manufacturing happening there. (Our cave was closer to downtown and was mostly used for warehousing.)

[hedvig23]

Are you saying there could be radio signals in caves these days?

[stephen_g]

I think they mean that there might be WiFi access points or cellular base stations now installed in some of these caves given the ways the spaces are used.