I know we are in different states and that laws are problably extremely different, but here is my 2 cents.
I live in IL, in a little city called Mt. Prospect
(It's known for being the city where the "Blue's Brothers" obtained their car, and just recently, for being the hometown for the new "American Idol" Lee Dewyze.)
Anywho,
I have checked, double checked, and tripled check my laws, and it states that since the MB has pedals, it is considered a bicycle, Hence its completely legal.
I ride my MB to work EVERY SINGLE DAY. I take streets and sometimes sidewalks, and I have done it in front of police and nothing. I talked to the Traffic Enforcement officer, as well as one of the police supervisors, and many other patrols, and they all have said the same, that it is legal to own and use.
Also, my neighbor from across the street just obtained his first MB motor, a grubee skyhawk 66cc, and before that, he asked to take pictures of my MB to take to the police dept. and so I said ok. He took the pictures, and we took them to the front desk where a CSO and a regular officer saw it and agreed that its legal to use without the need for insurance, registration or even a license.
I hope that helps ya!
P.S. like always, double check your laws, you dont want to get in trouble for a MB.
Take a pic and take it to your local PD. See what they say, and remember, as long as the MB has pedals, its considered a bicycle.