No
Harmful
It rusts
It rusts
its harmful because when metal goes rusty it looses it power and then eventually the car will fall apart.
They may become unsafe to drive due to rust weakening parts of the car.
No Because If It Is Wrecked Like Its Missing Parts And Its Old And Rusty Then It Will Not Be Able To Be Sold
The car is safe due to the strength of the body. If it is rusty the strength goes away quickly. Also all the brake and steering parts are mounted to pieces that rust also.
Friction is useful when you are trying to stop a car, but not useful in the pistons of a car's engine (It makes them less efficient).
because of weathering
Rusty cars are usually a bit weaker then ones without rust. It chips of easily and so that is why a rusty car is dangerous. Especially if the main body or chassis is rusty. Weakness on the chassis mainly could be a definite killer to a car. That would mean changing the chassis. I would just get a new car by then.
Yes it can
Other than maybe breaking old rusty fuel lines. It shouldn't affect anything accept make the car run or run better