Sounds like a jerk cop to me also. Why  doesn't he just drive around & pull into the driveways throughout rural midwest & start ticketing inhabitants that have SMVs installed on their mailboxes & driveway markers? He could probably even get them for having the "old style" SMV that supposedly wasn't as reflective.

To me an SMV warns someone behind me to please not crash into me & be cautious because I'm not just a Toyota Supra &  I have "special needs", which is the name of the game anyway these days. Whether this SMV is going 12 mph or 38 mph doesn't matter a lot. It's still probably slower than 99% of the modern public drives, and slower than 100% of the kids drive these days. I don't want them to hit me no matter how fast I'm going. Also, the vehicle or trailer that I'm pulling usually is not normal sized. I'm just trying to help prevent an accident. Cops should appreciate that.

Again, if we have all the facts presented, the cop is a jerk. One addtional item, in IL you don't need a cdl or hazmat if you're pulling your own (farmer) tanks.

Also, nebfarmer, can you report back after all the dust has settled to advise on final outcome? Have you considered contacting local Farm Bureau for help? Sometimes they can provide helpful legal info. At least they'd like to know about the situation to keep others advised. Whatever the outcome, good luck!