Yes, safety is the reason. But when setting up the rules, the Japs assumed the mechanics here will have the same level of honesty and focus as the ones over there. After a few problems similar to ones mentioned in the topic, I now insist on standing by the vehicle or doing frequent visits to the shop floor; and tell off anybody who'll try to push me out.
A bit of noise, sadly, is the way to get things done in most places in SL.