If you are including rental vehicles, then you have me at a loss. I've rented cars at many locations over nearly 40 years, and I haven't tracked the registration of the vehicle. I did spend a number of years driving a GSA motor pool vehicle in the 1980's, and I'm not sure where it counts for registration.
Updating on this enormously esoteric topic:
BTW Speaking of vehicle registration, I'm registered at the ALPCA hotel in Aug. Are you making it this year?
Heh, I am counting rental cars' plates. As a license plate nerd, this was my main motivation with this question. I always love having a car from a random state, and having people stereotype me based on that state. I suppose a USG-plated vehicle wouldn't correspond to any particular state.
I'm tentative on the convention. I'm supposed to be in Croatia the Sunday afternoon after the new convention dates, but I'd like to pop in for the Wed-Fri, or so, of the convention particularly because I plan to make a display and win a first place award, as I usually do. However, if my Croatia trip doesn't come together because of lingering travel restrictions, then I'm all in for the convention. It's not every day that someone offers you a week on their yacht on the Dalmatian Coast, so that will be my first priority. Was disappointed that they convention dates changed to a time that doesn't work as well for me. Looking forward to Hampton Roads, Denver, Lansing, and Tulsa, though!