For those that are concerned about having their expensive custom helmet paint job chipped, you can actually have it wrapped in a clear film just as they do with all expensive luxury/exotic vehicles. Its called PPF(paint protection film), with Suntek being one of the bigger recognizable names.
They also are popular with window tinters because they can get the film with different intensity of shades, have solar properties popular both for auto and installed in home Windows.
Some contain a ceramic feature that can actually stop or deflect anything from someone trying to break in by smashing your window, up to a degree of being ballistic proof.
At minimum, adding a laminate, just like what you would put onto a printed vinyl wrap not only will protect a paint job or vinyl wrap, if you do take a slapper to the head and it leaves a minor blemish, all you have to do is hit it with a hair dryer for a few minutes and let the self-healing properties of the laminate do it's job.
Some have questioned adding a laminate to a vinyl printed wrap. It's worth it, if for nothing else to just give you that extra piece of mind. Not to mention all the new creative options you have nowadays that can take your helmet graphics to a level that can be hard to come by and make it really unique. You don't even have to have custom graphics on your helmet to make it unique and one of a kind (luster laminates, carbon fiber, brushed steel, colored chrome, etc.