You are familiar with the letter of the law and workings of courts, at least on the planet that you were a judge in. If you are in a foreign place where you are not familiar with their exact laws, you often will be able to track down the resources you need to learn them.
If you or your party gets into legal trouble, your experience may help you get out of it. If you can prove your credentials, you might be able to represent your party in a court of law without admonishment. You may know of legal loopholes that will help your case. If you are in the region where you originally worked, you might have past connections with many legal professionals there.
