On a military base, if you forge your Military Vehicle ID tags, what's the punishment?

It's the little reflective tags that go in the window. My neighbor just got a motorcycle and doesn't want to wait for the motorcycle safety cl required to get his base tags, so he took a photograph of the tags on his car and printed some off using his computer. They look totally fake, but he was bragging to my husband about it. He's driving around with it, and doesn't even have his motorcycle permit on top of everything else? We were wondering what kind of trouble he could get into?