Don't know. I put splash guards on my Maxima myself in 1999 (the same type as M2). Only recently (in January) donated it -- no rust there. Front right fender rusted where it was scraped by somebody when parking (and I was too lazy to prime/paint it). But near splash guards -- no problems.
I'd also argue that on Mazda2 it's the rear guards which are more or less useless: they protect somebody driving behind you, but on the car itself -- what's there to protect? Plastic bumper?
I'd also argue that on Mazda2 it's the rear guards which are more or less useless: they protect somebody driving behind you, but on the car itself -- what's there to protect? Plastic bumper?