Look at it this way. If the bumper attaches at the same number of places as a factory or aftermarket hitch/bumper would, you should be good to tow a small (read: 1K-2K) trailer load. My JCR bumper attaches to the Jeep at the factory bumper mounts and at least 4 more. The 2" receiver isn't large enough to fit a hitch (prototype bumper :damn: ) but if it did, I'd feel comfortable towing my small popup @ 1500lbs wet. My old Tomken bumper was the same way.
Obviously if you cause some vehicular carnage because you towed with the bumper, the manufacturer and insurance company probably will not stand behind you since the bumper wasn't DOT rated for a certain capacity. Plus, I think it costs a decent amount of $ and man hours to get something DOT rated, not something cost effective for a smaller company.