The police can issue a "Notice and Order" to have the vehicle inspected if they have any reason to suspect the emmissions system has been tampered with.
Black smoke pouring out of the tailpipe would be a good reason.
If you don't comply with the order, you can no longer insure the vehicle, and you will be fined $598 for non-compliance, in addition to any other fines associated with the offence.
If the vehicle passes inspection (which it won't if there are problems), then you receive an inspection decal which must be affixed to the vehicle in the prescribed location. If you are caught driving without this decal, that's when you get the $598 fine for non-compliance. The vehicle will also be towed and impounded until repaired, at the owner's expense.
Generally, a vehicle that's been messed with is easy to spot. Either it'll smell bad, blast smoke out behind it, be driven by an idiot in an idiotic manner, or just look like crap. Inspection notices are the death of such vehicles. Bringing one of these hoopties back to compliance can be costly.
Losing AirCare won't be a big deal. Good riddance. For vehicles that are obvious polluters, or have other issues, the current inspection system can take care of them.
Also note that AirCare is only in the Metro Vancouver area, while the rest of British Columbia has never had AirCare. Anyone with a car that didn't pass could simply say are using the vehicle in a different town. Your home address can still be Vancouver! You just insure the car for a different area, and voila, junker is still on the road.
