To pay or not to pay, that is the question

"If you have the shop paint it, I would have them prime it too. I wouldn't want them blaming me if the paint didn't adhere or lay right since the right prep work is really important."

Amen to that. If I had a customer bring a vehicle to my shop, I would darn sure want to know what was done to it before i painted it. A paint job is only as good as the repair/prep work. The only exception to that, for me, would be someone who does body work for a living or was a serious hobbyist both of which knew what they were doing in regard to repair work. Not all body-repair people like or want to paint their own stuff.