This is exactly what the Pontiac engineers almost got away with back in 1973. The set up a timed solenoid that would deactivate the EGR system a few seconds after the EPA timed emissions test ended. EPA caught them and made Pontiac redesign the system and repaint every engine prior to installation in order to prove that the refit was done.
http://www.foxnews.com/politics/2015/09/...s/?intcmp=hpbt1