Onetin is right about their concerns about image liability. If a contractor hits someone on a brakeless the police are going to make a point of that on the report believe me. The company may face no liability in the courts as the contractor is responsible for getting the job done but that won't stop the injured part from naming them in a civil suit and it won't stop the local newspaper from naming the company when the collisionee gets clever and takes their story to them.
I've lent out my bike for the purpose of a police report to a rook that while a good rider did manage to hit someone. It wasn't his fault in the least (she stepped out from the front of a bus with 1 foot to spare) if it had been I wouldn't have helped him. I did it though because it was the bus drivers fault and our community didnt need the bad pres and the vitim shouldnt have her claim against the metro complicated by cloud seeking lawyers