When a customer orders a print product in a union shop, the customer has the option of including a bug to show the item was printed under a union contract. Most democratic candidates use union shops and include the bug.
Here is a sample bug:
http://www.unionsolidarity.net/label.htm Is the Allied Union Label on your printed material genuine and certified?
Printed products bearing an authentic Allied Printing Trades Council label are symbols of the quality, skill, experience and pride that union members put into their work every day. Unauthorized use of, or tampering with, this union label (also known as a union bug) is illegal.
By working with Union Solidarity Graphics, you can be confident that your printing projects bear a genuine and certified union label. Displaying the Allied label on your projects demonstrate that you recognize just how vital and important the union community actually is.
I was GAU when I was fired for trying to organize a shop. The GAU merged. Then it became Teamsters affiliated. One of the old GAU bugs: