If your going to worry about things getting kicked up and coming into the cockpit (this includes snakes) then I would be far more worried about what comes off of the tires of the vehicle in front of me than what might come off my own tires - - - over the years when riding in cars I have been in I have had the car get hit by everything from a full sheet of drywall, a 1.5 foot long piece of 2x4 that came through the windshield and a big chrome lug nut off an 18 wheeler and I was lucky that lug nut didn't kill me. seriously at one time or another almost every vehicle I have known of has had had the windshield broken by a rock or something else kicked up by the vehicle it was behind. - - - this is one of the main reasons why when I am in the slingshot I avoid driving on the freeway if at all possible and also why I always wear a helmet and ballistic rated eye protection.
I hear ya.. when I first started riding motorcycles in the 60's people didn't even wear or were required to wear eye protection. I can honestly say I never worry about anything coming in my Sling (except maybe a snake ) as most stuff as mentioned I have also been hit by.... No sheet of drywall though.....
I really hate the bees and the June bug hurt like hell on the motorcycle....
This is how I remember riding in my younger days.... pop a brew, fire up a dube and have a good time...