Ok I am a little curious at people suggesting a throttle return spring. From recent experience not even a return spring prevented a runnaway after my venom smart temp spat itself and died. My throttle servo still got stuck on WOT and as such the spring does not return it as the servo locks itself in that position as if you were holding throttle. The Servo wont allow it to return. very interesting. It simply does not do that for me.
Also I do not know if you got the smart temp but if you have, my advice is to take it back & get a new one! Seriously they are not worth the money. Nothing but junk I am affraid to say. The standard throttle failsafes though I have never had an issue with. My smart temp however did not last more than a few months before breaking down completely CAUSING a runnaway situation.
Anyone reading this, you have been warned! By the way, use hump packs in the receiver and you will never have any problems with batteries coming loose. I really wouldn't be using AAs in the receiver if its at all possible.