Thanks for all the comments so far!
It looks like the results of that Ziebart cover will depend on how it was applied. I'd assume that if the surfaces are properly cleaned before applying it, no dirt or moisture should get trapped underneath.
On this same subject: In Canada I had an Honda Civic with an electronic device for rust protection. It works on electrolysis principles. no coating needed. I had no rust issues with it. I held the car for over 10 years.
Oh, and maybe someone here knows: My Edge was produced/assembled in Ontario, Canada. How can I know if it already has rust protection?
Thank you.