I've got at least 4 powdercoated frames in the garage. None of them are rusting on sharp edges.
I've also seen clearcoated frames rubbed right down to bare metal where cable housing rubs. The only way I've seen to avoid rub through is those clear adhesive "guards". Not trying to argue here, but the only powdercoated items I've seen rusting, are tubular truck steps up North. They don't powder the insides, hehe.,,,,BD