From the Richmond Daily Dispatch July 17, 1862:
Show Your passes.
–Citizens as well as soldiers must now show their passes, if they wish to avoid getting into trouble. Squads detailed for the purpose are patrolling the streets daily to intercept straggling soldiers and examine exemption papers. Parties who cannot show cause why they are not in the army, or with their regiments, will be arrested and put in prison.
You can read a good overview of Confederate conscription at The American Civil War. The article makes the point that exemptions are a rational way to allocate human resources during a war. They were abused in the Civil War.
You can read the details about the following political cartoon at the Library of Congress.