Scott, Run, don't walk away from them.
If they are a manufacture of any product and want the manufacture of any parts used in the manufacture of the product they make, good luck in a law suit. They might be able to get this in court, but I don't think the courts will allow the manufacture to include another vendor or supplier of parts unless they could prove that the parts supplied were defective or caused the failure. In most cases the final manufacture is responsible for the proper testing of their product to insure product reliability. If I was a supplier of parts to them and they requested that I provide them with liability insurance for the parts I supplied I would tell them to look elsewhere. Sound like a company that has a scary past and is looking at someone else to blame for there failures. Just my $0.02 worth. Please provide the name of the company requesting this so we can all STAY AWAY. Thanks, Charles Miller