Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_3_1 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8G4 Safari/6533.18.5)
I had a skin on my phone when I dropped it, broke the screen and took it in to have it replaced. I realize this isn't a typical warranty type of repair, but the apple genius girl said because I was honest about what happened that they'd fix it for free 😛. But yeah, at no point did they mention the skin on my phone. I was just out a screen skin once I got the thing back.
You should be totally ok.