Nice point cshoff. That's the first time I've heard something logical with this debate. The argument that has always been brought to my attention is how it applies to the Castle Doctrine protections rather than CCW. See RSMO 563.011.2
http://www.moga.mo.gov/statutes/C500-599/5630000011.HTM
(2)
"Dwelling", any building, inhabitable structure, or conveyance of any kind, whether the building, inhabitable structure, or conveyance is temporary or permanent, mobile or immobile, which has a roof over it, including a tent, and is designed to be occupied by people lodging therein at night;
The issue as it was explained to me was how the language is written. Conveyance (look for the second reference where it goes into temporary or permanent) is separated by a comma from the rest of that section which could result in the application of "which has a roof over it" and "designed to be lodged therein at night", something that becomes very problematic as it would then rule out a convertible auto while the top down. It just wouldn't make sense. A similar argument was made on the placement of commas in 2A if any of you recall.
A re-wording to sort out any potential confusion or intentional misinterpretation is needed. It needs to clearly separate conveyance and word it in this manner "conveyance of any kind" rather than separating conveyance from "of any kind" by a comma. All it would take is a prosecutor or dirtbag lawyer to push the envelope on the matter to make a semi-logical argument in court.
When I rode (had CCW) I carried 100% of the time, granted that was before I became an instructor, but my mindset was that it was far too easy to injure a rider or attempt to jack the bike with me on it.