I would have to agree with you that the whole Drive Clean program is a sham.
Here's my story...
My 1992 Dodge Caravan was tested at a Goodyear centre near me (Nov 2009), and failed on NOx emissions. I spoke to my mechanic about the failed test and I explained that the muffler shop had changed the catalytic converter just 6 months after the last emissions test, claiming that it was faulty. He said that was probably the problem, the replacement converter is inadequate. We put some engine additive in and took the car to another facility for a test, hoping a different test machine may give us better results. It failed again, but this time much worse than the previous test. I explained to the tester that the catalytic converter was replaced. This mechanic agreed that the problem is probably with the catalytic converter. I called the muffler shop and they said they couldn't help, the warranty on the converter was only 1 year but if I wanted a replacement they would give me a good price. The problem is that $450 must be spent a an approved emission centre, so I asked the centre what could be done. He said he would have to perform an engine analysis ($75) to determine what should be fixed. A couple of hours later he calls me up and says that he thinks, but he's not sure, it's the catalytic converter, but his replacements would probably fail as well, and since we need to spend $450, it would be put to better use tuning up the car. So I had a tune up done, wires, plugs, and oxegen sensor. The total cost for all the work was over $500. The end result, the NOx still failed with 2, 555 (after the tune-up) and 998 on the first test at Goodyear(the pass limit is 735). More than $500 spent was a complete waste of money. The environment is no better off, and the emissions from my van are worse than when I started, if the tests are to believed. Worse still, in 2 years I will have the same issue all over again!
Major lessons learned here
1) Never let a muffler shop replace an OEM catalytic converter (probably applies to all major emissions components) . Get a second opinion!
2) Drive Clean is just a farce, and a money grab!