Emissions Testing Revamp

Ontario has announced changes to its Drive Clean program. Like taxes or ­visits from the crazy uncle, the annual vehicle emissions test is something you endure.
The province’s Minister of the Environment announced that starting September 1st, drivers will get a ‘break’ on the testing. Instead of having to bring a car in for testing when it reaches five years of age, it will be increased to seven; and those with ‘historic’ license plates will be exempt. I have a 20-year-old Civic and a 10-year-old Accord, so these changes don’t mean anything to me, or for the majority of drivers on the road right now, I suspect.
What is not clear, however, is what is happening with the actual emissions test itself. I’ve been trying to get some clarification from the Ministry and those handling Drive Clean on the upcoming introduction of OBD II-based testing on new vehicles instead of the current dynamometer-tailpipe test that everyone in the province is familiar with. Several studies have been done on using OBD II for emissions testing and a major report was prepared to look into changes to regulations governing motor vehicle emissions in Ontario. When I spoke to several shop owners, all had questions as to what the move might mean for them, but were reluctant to speculate further.
But here is a question I have: ODB II can detect a variety of different things and throw a trouble-code because of what it finds, from an intermittent misfire, to a faulty wire or some kind of minor problem in the EVAP system. But is that enough to ‘fail’ a test?
If a car once passed the older tailpipe and dynamometer test, possibly with such problems, why should it not also pass the new Drive Clean inspection? In the end, what is of importance is what is coming out of the tailpipe and going into the atmosphere?
I can see situations happening where someone comes in for an emissions test and then is told their vehicle cannot pass unless a very expensive diagnostic and repair is done because some kind of trouble code has been registered. What is to stop abuse from happening, from a less than honest shop telling the vehicle owner the problem requires hours of diagnostics but, in reality, is nothing more than replacing a faulty gas cap and clearing the trouble code.  
Right now, there is little clarification as to what the criteria might be. Maybe as the roll-out happens, these questions will be answered and shops will have time to prepare. But right now, I’m as much in the dark as everyone else is.