I guess what the mean is the same way spark gap transmitters are forbidden. Anyone can do it but it's forbidden. Anyone can read the wifi signals but CISCO doesn't have to sell you a dashboard with real time view of your location and everyone walking through it with all the websites they visited since they walked in, last time they were at your location, average time they are there, to communicate to a store in the mall that you're almost in front of it so it sends you a push notification with an ad, etc.