W00t w00t here I am, I'm like a hawk! Yeah should be 7 year unlimited mileage. I had both of my rear fenders fixed under warranty. The warranty doesn't cover surface rust, but if paint is bubbling then it's obviously coming from underneath, so it's perforation. The body shop they took my car to sucked though.. they just repainted the easily visible spots, not the actual lip going into the rear fender or the unsealed edge which is causing the rusting to begin with.
Two years after getting it fixed, it's much worse than it was the first time. I'm thinking I might just not bother going to the dealership.. I might roll the fenders and then find a reputable body shop in Rochester (HA!) to repaint the fenders (making sure to seal the edge of the metal so it doesn't rust again).
Your dealership most likely (especially if you are young.. I was 19 at the time) will try and deny the warranty work, making up some bs about mods causing it.. either threaten them with a letter from your lawyer like I did, bring your mom with you to b**** them out (like I also did), or contact Mazda corporate to get through to the regional office and let them know how rude and unwilling to provide a minimal level of service the dealership is.
After all that, I finally got them to put my car on their lot on the day the regional rep was coming in. He saw it and instantly said "yeah, that's perforation alright" and then the next week it got "fixed" by a bad, awful crap cheap body shop a couple towns over.
your mileage may vary. It's the only warranty work my car ever received, and they made it a huge hassle and in the end did a crap job. I guess not all dealerships suck as much as Modern Mazda in Thomaston, CT, but who knows..
, I'll just threaten to contact Mazda Corporate....And since it's warranty work.. I'm pretty sure Burdicks Body Shop will handle it, so I know it will be done right.. 
