Hmm, seems I have it backwards then. If that is the case, how can I, as a buyer, be certain that the vehicle I'm buying will pass emissions?
Buyer beware. It may not pass.
You can personally require the seller to have one before you will buy it making it a contingent to the sale. This makes your negotiating price position usually not as good though.
I say lets all remove the warning labels and let nature take its course.