Almost everything in a real estate transaction is negotiable between Buyer and Seller. How much a Seller can pay will depend on the Seller's motivation to sell and the Buyer's lender and type of loan obtained by Buyer.

Before the owner of the vehicle even lets the serviceman near the vehicle, they should ask for some sort of credentials from the technician. Also, is there any sort of advertising on his clothes or car announcing the business? ex. company shirt or sign on his vehicle... From past experiences alot can be learned from the first minute of arrival. My company provides services for car door unlocks and its policy to get verification of ownership Prior to unlocking the vehicle. Also, Its not likely with a trained locksmith but if damage does occur any reputable lockmsith with have the necessary insurance to cover the damage.