You are correct as far as formal complaints. But the reality is that you can *67 call the sign inspector and report something illegal, and they are going to check it out anyway. Like any business, the real way it works is not the same as the politically correct version they publish.
It is a bad idea to turn in a competitor unless you are 100% sure they are cheating, and 100% sure you are completely in conformance on your own signs. When someone gets turned in, they can normally figure out who did it, based on activity in the area and their own intuition. And the first thing they are going to do is to go after any violations you’ve got. Here’s an example. A competitor called the City of Denton and said I’d chopped down a bunch of trees illegally. They came after me. I went out and showed them that the trees that were chopped down had no impact on my sign, but used to obstruct somebody else’s. They then went after him. Thereafter, I was always on the look-out for this person’s violations, just to return the favor.