TC. What about the bit in the Eurocopter EC135 emergency checklist concerning a 'BAT TEMP' caption and gong.
IN FLIGHT
1. BAT MSTR sw OFF
2. LAND AS SOON AS POSSIBLE
after landing:
3. Engines Leave running in idle
4. Collective lever and cyclic stick Lock
NOTE Continue flight only if visual inspection reveals no indication
of battery overheating etc.
It does seem to suggest they consider it reasonably safe to leave the controls unattended for a short period of time.
TeeS