I've been running for years with the hardtop off, never had any issues about the brake light. Having worked in LE for a while (Military Police), I wouldn't hassle a Bronco driver about the third light. Now if I had you pulled over for something else, say maybe some kind of moving violation, and you decide to give me attitude....well.....you can see how that might go.

/emoticons/
[email protected] 2x" width="20" height="20" /> That's not to say you would never be pulled over. Every LEO is allowed to use his own discretion in most cases and that is just my personal view.
As for the seat belt, when I first started running *******, I never let anyone ride in the outside rear seat positions when the top was off, only let them ride in the middle where there is a lap belt. I recently got a rear seat from an older bronco (any '91 or older will do) and use that when *******. The older seats had three lap belts connected to the seat itself. Still not
technicaly legal because the newer vehicles are supposed to shoulder belts in the back, but its safer than nothing at all and you can let your friends ride with a clear concience.