its common, especially in wet/snowy climates. They really do nothing corrosion resistance from the factory.

We do exactly what you described with the anti seize and wire wheel, it helps alot but it doesnt prevent it 100%.

On my 240 I had my hubs coated to prevent it, since I do alot of installation and removal or parts. We had a severe problem with our c6 z06, and it never sees rain. Just the water from washings caused the hub/brake rotor mating area to rust up.