What keeps many of us on the straight and narrow is that we recognize our misdeeds will be outed by the idealistic, envious, resentful, or frightened. Unlike Lance Armstrong we don't have the arrogance to assume that we can control other human beings. So, we play by the rules.
What helped the fall of Armstrong is that those he tried to keep silent were only too happy to blurt it all out as the hand of law and order reached in. Since he couldn't have managed the doping process in isolation with no one else in the loop, he should have dropped that strategy for getting the edge.
Not trusting anyone keeps us out of prison.