KeySense on one key fob only, why?

The Keysense key is the one you give to your teenage driver. It limits the speed and the loudness of the radio, among other things.

I give it to my dealer or valet parking attendants. I have a max speed set and volume control set. I don't need a dealer mechanic or valet abusing my vehicle or blowing the speakers. Plus I set up a geo-fence around my dealer location or valet location through the Uconnect app so I know if they take it off the property. People do stupid things and don't care when it is not their money.

Read your owner's manual. Most of your questions will be answered there.