I commute on a route thats very heavy with AA and Envoy commuters. Over the past couple of months, I've run across more than a few new Envoy pilots who have been checked in as a D2 for multiple flights between the same city pair, on the same day. One individual was listed, and checked in for every flight of the day.
Review the employee travel policies, the company does look for this stuff, and other employees may turn you in. You can get your travel privileges suspended/revoked, or possibly fired.