I'd bet that most of you suggesting that the 2nd cable is just for sissies have never had a throttle jam on a motorcycle. With the power-to-weight ratio of even something like a CB750 and if the RPMs are up and you're in a lower gear, the thing will get away from you before you have the where-with-all to find the kill switch. It can happen almost instantaneously and JUST LIKE THAT, you're in the big trouble.
It's a good safety system. That's not to say it is absolutely necessary, but if it is there and working properly, it is silly to remove it. If its not working properly, I'd first suggest fixing it.
- Mark