So I'll jump in on this horse. Sometimes it's interesting to hear this topic come up as long as it doesn't start WWIII. As a side note, you CAN be stopped in Tennessee for only a seat belt violation, been there done that. Law was changed about 15 years ago to allow for it... As for the original topic, I do live in Tennessee and no I do not wear a helmet however I do keep one with me just because. I know people in our group that have received a ticket and paid and I also know some in the group that have received a ticket and had it dismissed in court. My personal experience I have been stopped numerous times without, was actually just hit with blue lights this past Friday. I have not received more than a written warning. I drive almost an hour to work. Multiple cities and two counties. The main city where I work WILL stop you, that's where I got the warning a couple years ago. I've actually got to talk with the leo's quite a bit that stop me. They have a picture from slingmods with the full batmobile enclosure and said if that's installed they will not ticket you, anything else your at your own risk. The main cop that pushes this said he'd rather not and doesn't see it as much more than a jeep but that's what they push him to do. He said if the next city over(where I just moved from and has specifically stopped me to discuss the law said they interpret it as you DO NOT have to wear a helmet and will not stop me) doesn't care then he would take it off at the city line as well. Now the new city I just moved to last year has stopped me. First time was a holiday weekend and it was to let me know he understood it as you had to and he had trooper buddies up there that were told to stop anyone for anything they could. Said he personally didn't have an issue and let me go on my way. This same cop pulled up next to me Friday(tiny town) and put the blue lights on to let me know he talked with some people and verified that you do have to wear a helmet but he wasn't going to bust my chops about it, just wanted me to know and to have a nice day. We'll see what happens the next time he sees me.
Either way, the law IN MY OPINION is not very clear. Leaves alot open to interpretation. Defines what an autocycle is and that having not been fully enclosed requires a helmet. But then a separate section afterwards that says autocycles are exempt from all previous sections. Just leaves alot open to opinion and unfortunately not a hot topic that's easy to get your local politicians to check into.
That being said, if you wanna wear one then do so, and if not then so be it. I choose not to but keep the helmet with me. Anytime I'm stopped I'm more than respectful to the officer and tell them I'll gladly put it on and be on my way ticket or not. I tell them with all the bs they have to deal with these days the last thing they need is to sit there and argue about what a slingshot is or what it means to be enclosed. Most of the time they seem to be more intrigued with the slingshot itself and want to talk about that instead of helmets. I look at this way I believe it's written one way and someb of them believe it's another but it's above both our pay grade. If someone doesn't like the uncertainty in Tennessee then either get rid of the slingshot or write your local congressman. But no need to cause a bad encounter between you and the officer. Accept the outcome and ride on...