"likely from wearing the band too tight, or sweat, water or soap... under the device,"
So Fitbit has designed a product to be worn by people who exercise... which does bad things when combined with *sweat*? There's a reason I don't wear solid straps (plastic or otherwise) with my watch - I live in Australia and sweat is a constant part of simply walking around.
Disclosure: I am the owner of a Fitbit One and love it to bit. But I wear it clipped to a shirt pocket (or in the coin-pocket of my jeans).