Even if dealer accepts responsibility, you still have a monumental hassle going through the repair process.
I have done 100% of my auto repairs/maintenance since I started driving in 1966 except for one complimentary oil change and several warranty repairs. The oil change was on my brand new Lexus RX300 in Jan 2000. Picked her up and discovered two major scratches down the entire hood from windshield wipers to bumper. Dealer said I could not prove he did it and he could not prove the scratch was already there. It went downhill from there. Several warranty repairs on various Lexus and Toyota vehicles at 4 different dealerships all went bad. Not one issue fixed right the first time and several cases of collateral damage similar to what previous posters experienced. I have two complementary services available for my new Lexus ES 350 but I will not let the dealership touch my car unless absolutely necessary for a recall or warranty repair.
That frankly can happen at any point when someone touches or comes near your vehicle, let alone perform service on it.
I'll agree with you on that.
In 1993, I had a brand new Ranger pickup. It needed its first OC.
A brand new WalMart TLC opened in our town. I took the truck in.
I was watching in the window while a rather rotund, vertically challenged gentleman performed the OC.
I paid, and went out and walked around the truck. The fender that he was leaning over had the paint ground off of it.
I went in and demanded to see the Manager. I took him out to the truck and showed him the damage.
He said "Looks like a paint defect to me." I told him that "Let's go inside and I'll show you the defect."
He knew where I was going with it and told me that all their staff was required to wear a protective belt type of thing to protect the vehicles they service.
I walked over to a pony wall that separated the service area and called the guy over. No protective sash. He even had the red paint that matched my truck ground into his big, brass belt buckle.
Cost Walmart $193. to repaint my fender. Fortunately, my FIL owns his own auto body business. He did an excellent job of matching it up.
Point is, anything can happen. Not everything can be prevented.
If you pay for something, you should use it. Or, negotiate it out of the price.