I was in your same boots this season as well. I did a big install for a commercial building, put my sign out all of a sudden its missing. I was pissed then and there because this was by a very high traffic area. So I ask a guy at the place he says its inside, the guy who cut the grass took it out. So ive learned to bite my lip n say forget it. Well the people I did the work for hired some guy to do the maintenace for the property(after offering one month of free maintenance to them for having me do the install, its a non-profit org.) never heard from em. So this smokejob puts his sign in front of the place for about 4 months, so now hes been "taking credit" for the work I did. Whether he says he did the install when people call him or not, people still think its all his work and I got screwed. My work was in the front of the building where people could see it so I understand what your saying how the work is in the rear of the property.