oil cant hurt paint unless you leave them in contact with one another for a long period of time. but then again look at your door hinges. they get oiled all the time and nothing goes wrong with the paint on them. the reason for this is because pb blaster doesnt have spirits in it or paint thinning agents in it. also you have a clear coat on your car which prevents alot of this from happening. its just a cheaper easier route to go and to each his own.