By definition this is not true - because I am that user. 
I am using the HKS to turn off WiFi (and BT) when leaving the house. I am not using the HKS to turn off the modem (typically ever).
Yes. 100%. However, in practice, commercial entities (like TfL) are not deploying Stingrays or other IMSI catchers. I am responding to the privacy threat as it is today.
Depending on your location, and on the details, IMSI catching is not as precise as listening for WiFi probes.
If we ever reach the point that IMSI catching becomes ubiquitous then we may all have to re-evaluate. Some people think that 5G will be that point (in urban areas).
Coming back to the core topic: If you are a DC Rioter with an L5 then you really should use the HKSs to disable both WiFi and the modem. If you are a DC Rioter with a mainstream phone then leave it at home. Take your digital camera instead if you want to get a few cool, but incriminating, pics. 