Can't wear a tether on some of those tricks. Good idea just not feasible for some stuff.
OH but you can, the Teth-Air tether does not use a leash but a wireless signal, so if you get separated from the sled by "X" distance it will kill it. You have complete freedom of movement on and around the sled, can get it unstuck ect without it killing it. From my understanding you can trim the antenna to provide the amount of distance away "X" you want. A small black box on the sled and a small wrist watch size transmitter that is worn somewhere on your body (in a pocket or whatever).
I have nothing to gain by this, I've just read their pitch and will be trying one on my next build.