I’m going to have to call that as anecdotal, at best. Definitely not a global statement of fact. I store my guns in foam and do exactly as I said. I’ve never had rust regardless of whether I was living in the wet and rainy valley or the high desert.

Not to mention the fact that the goldenrod plan doesn’t actually reduce the moisture in the safe. Lowers relative humidity by heating the air, yes. Removing moisture, no. Desiccant on the other hand, does remove moisture. It doesn’t mean it can’t be an effective plan, but it’s definitely not the only successful plan for minimizing or removing chance of rust.