Wouldn't worry about that - if Idle is on or trottle is not fully down, heli never turns on. red light is shining instead of flashing green while calibrating gyro...
Only problem is if you turn it to idle during flight and don't realize that - you should smash it into ground unbelievebly fast instead of slow landing =)

I hope it's all true - I don't have stock Tx for a year - bought a Optic 6 after frying old stock Rx (I don't know, 10 min of full trottle on Idle is maybe too much for 3in1... =/ )

Kryso