So who should pay for this error?

[BigEndBob]

This could drift into a maintenance problem.
Have recently worked at a club where none of their Cessna would start unless the throttles where wagged around...which really annoys me.
Students see this being done then copy.

Any nicely tuned Lycoming should start with a few mm's of throttle or even with throttle closed if warm, without risk of the engine suddenly bursting into power and pulling of the brakes.

Parking brakes..now thats a whole story in itself.