What? Why would you want to out a thief? And if it's close to you all the better. If a physical confrontation followed by a good ass beating is not your style then maybe vandalize his car or property.
IDK, I'm 61 years old and old school. We make bad guys pay. People's behavior is in most part rule by reward and punishment. When you reward a behavior you get more of it. When you punish it you get less. Look at LA. They have announced that they will not prosecute thiefs under $900. Now punks are literally just walking into stores in full view of everyone with various items knowing nobody will do shit.