Auto start/stop - for emissions, it is compliant with CO HC NOx etc regardless of whether you have it turned on or off. For fuel consumption, it makes a difference, but the numbers reported are based on the default mode. You get into the car, turn the key, slap the shift lever in "drive". Whatever mode that puts you in, is what the test is done in. That's why it defaults to having start/stop engaged. The auto manufacturer (remember, they're the ones testing, not EPA) is supposed the testing in every possible mode and makes sure the emissions are compliant in every possible mode, but the fuel economy numbers reported to the consumer are done in the default mode.
FWIW you know those "eco" buttons that a lot of cars have? Most of them make absolutely no difference. They change the way the accelerator pedal responds to perhaps encourage more economical behaviour but they don't change the engine's emission control strategy. Same thing with the motorcycle "a" "b" "c" power modes etc. They're only changing the way the drive-by-wire throttle system responds. They don't change the ignition timing, fuel mapping, etc because that would affect emissions.
