The tether is just a precaution if the transducer is knocked off. I always wear it unless I am at home. Yes, the magnet holds it on unless it gets knocked off. If the magnet is too strong, it makes my head sore. After I lost mine, looking back, there was a lot of confusion that day. It was raining hard, and I was loading two dogs back into my car, and I had med bags, paperwork, and a purse in my hands. I think I hit it on the seat or something as I bent over to get the dogs into the car. In the confusion I did not miss it right away. I searched the car first, and then went back, I searched everywhere multiple times. My concensus was that it either washed away in the gutter or someone found it and did not realize what it was, or it got run over. I do not know what happened, just that losing it made it a sad day for me. I even bought a magnet roller and went over the parking lot and what little grass they had. And yes, I have more hair than you. Lol
Now I hook the the tether onto my earring. It works a lot better than the clip. There is also a headband I wear sometimes. Lesson learned.