On my Pathfinder the rubber seal on the tailgate was completely deformed and almost deteriorating due to the Rustcheck product damaging the seal.
Gee, look what has this NHL lock out done to us - a Habs' fan helping a Leaf fan
This is the first I've heard of seal damage...
A couple of followup questions:
-- is Krown any better than RustCheck wrt seal damage ?
-- so is the advice to make sure the fluid doesn't pool anywhere on or near a seal over time ?
-- should you tell the installer to not treat around or stay away from the door seals ?
Another option for rust proofing would to be to buy a few cans of Krown or RustCheck and just apply in the usual trouble areas - fenders, gas cap, tailgate hinges for example. Every Honda I've ever owned always started to rust ( visable ) first in the back fender where it meets the bumper. Mind you this was after 10 years or more.
One trick I've learned is to look at older models on the road to predict future damage -- cars with the same body style will always rust in the same spot.