i had always wondered about the saturns and rustproofing.... but from what i recall, rustproofing was still suggested on them as the beams, frames and such were still metal.... i also know that the head office of saturn never suggested rustproofing their cars, only the dealers... so that seems a bit questionable.
i can't imagine the rust spray would cause the panels to fall off.... unless they were previously re-attached after a minor accident and done poorly.... but again... i'm not familiar with the characteristics of the polymers and the spray and how they would interact.
the oil spray on the rubber part i totally get as the two products don't get along...
whatever happens... i guess good luck!