Driving friction drive motor by the servo tester

Hi guys my knowledge is limited but I'm learning more and more as I build my friction drive, I have it wired up as far as connecting the servo to the ESC and it powers the motor fine, but I have read it is dangerous to use this servo as a throttle, how come? Is it just the fact that using a thumb throttle has the built in safety aspect of having to keep your thumb down to power the motor?

Also I read a throttle wiring thread but a few guys couldn't get there eBay throttle to work through their turnigy servo, I have this servo and throttle as well any tips?

Anybody?

I'd hook up a real throttle to your servo tester. Much better.

Yeah having the throttle spring return to 0 is a pretty easy way to dramatically improve safety. You should be able to just wire the throttle in place of the pot on the servo tester.

Thanks both, I'm gonna wire up a throttle as well just wondered if it was just a safety issue for not returning to zero, rather than it could cause the motor or battery to blow up or something lol