Troopers in MD are fierce... especially during the summer. I've personally been pulled a couple of times, and damn near everybody I worked with was pulled as well. Unmarked pickups with equipment trailers, box vans, dumps, didn't matter. If it wasn't a car, they flagged you down, checked license and reg, checked for safety equip, DOT numbers, unplacarded hazmat, load covers and tiedowns, and checked the weight at each axle.
If they wrote a ticket, it was usually in the $1500-2500 range. If your fire extinguisher wasn't charged or something, they'd just tell you to get it fixed. But if there were more severe problems with the truck - overweight, unsecured load, etc - they wrote you up for *everything*.
Now, some of that was because the trucks were being used commercially... and a guy towing a boat might get a little more leniency. But outside of NC, if you're towing a buggy with a bunch of sponsor stickers on it, it's frequently treated as "race" equipment, and lumped in with commercial traffic. Plenty of threads on the PBB to support this, too. YMMV and FYI and whatever....