Data still travels over radio—that’s not the point I was making. The distinction is about linkage, not emissions. A data-only SIM doesn’t stop radio signals; it can reduce some linkage (depending on how the SIM/account is provisioned) because you’re not adding voice/SMS usage records on top of the carrier’s normal data-session metadata. The phone remains a radio—the exposure is about how easily that activity ties back to you.

Ok, I get it now. Thank you for the clarification.