I don't know who would do that, PWNA already certifies contractors, but how much would it cost for someone or multiple people to travel over the country to check us out. Until such time as the certification program is recognized and no one can do business without one, there will always be someone doing business under the radar undetected, who's checking on that guy!
I met a guy who had his certification, and plans to take over the kitchen exhaust cleaning world, he wanted to have three truck on the road by the end of that year, he had a brand new full size chevy van loaded with equipment, most of which he will never use, and judging from his answers to my questions, he really had no clue what he was in for, and according to my Pressure Washer repair guy who set up his van the guy has no mechanical ability at all. I have never heard from that guy again.
Most of this business is the ability to adapt, and get around problems, if a guy has no mechanical ability, how good can he be.
I believe in a certification program, but it has to be recognized, do any of your customers know this program exists?
I also don't claim to have the answers, just stating my opinions