Yes, I did cover all visible skin on my head with Vaseline before the dyeing began, but it's pretty much impossible to dye without getting dye on your ears. The Vaseline would have protected it just fine, except that I bumped the cartilage piercing while dyeing, and the piercing spun, taking Vaseline and dye into the happy new hole with it.
Ow. It really isn't all that bad, but I think that the showering process in (checks watch) 20 minutes will probably be kind of interesting. Ow.