Shouldn't the smog shop warn me of an automatic failure?

California emissions standards require technicians perform smog inspections on vehicles exactly as they are driven into the smog station. No adjustment or repair can be conducted, unless specifically requested by the vehicle's owner and in advance. No repair recommendation can be made before or after the smog inspection; when the inspection is performed at a test only smog center. And no repair recommendation can be made before the smog inspection; when the inspection is obtained at a test and repair smog center.

Except for ensuring proper engine temperature, a smog technician can not and is not allowed to refuse inspection of a vehicle based on knowing the vehicle will not pass the emissions test due to any pre-existing circumstance, whether those be an illuminated check engine light, disconnect vacuum hoses, missing smog components, or any other emissions failure which will stop a vehicle from passing the test. The emissions technician must perform the emissions inspection and allow the vehicle to fail the inspection.

This is a requirement of California's emission inspection requirements. You may want to ask for a pretest. All smog stations offer this service usually for a small fee; less then the actual cost of the complete emissions test. Pre-test results are recorded but not used for vehicle registration purposes.

As far as your smog technician stating he may lose his license if he does not fail your vehicle for the check engine light, technically he is correct. If the station receives a citation because they failed to follow proper inspection procedures, they will lose their STAR certification for one year which may very well force them out of business, as a large percentage of vehicles require STAR smog certification.