Not only does it cost money to buy, but it also costs something like 60 bucks to replace the aluminum chunk that gets tossed into the blade to stop the blade. It would never work for me as I work with air dryed and wet wood a lot. It would constantly be kicking.
Its a good idea but I worked for the railroad for 10 years as a Safety Coordinator. Its just like I use to tell the guys out there, as long as you stay 4 feet away from the outside rail, there is no way you will get hit. There is only one path that train can take as it cannot steer. Its the same with a tablesaw. That blade tracks in only one axis, keep your fingers out of the way and you will always have 10 fingers.
I have no intention of traveling from birth to the grave in a manicured and well preserved body; but rather I will skid in sideways, totally beat up, completely worn out, utterly exhausted and jump off my tractor and loudly yell, "Wow, this is what it took to feed a nation!"