I explain to all the home owners what my rates are and that they are paying me to put my rod into their sewer. They still have to pay me regardless if I open it or not.
I had a job where I rodded the line and the rod would not past 60 feet. When I pulled back the cutter was all shined up. I put a cone retriever on the rod and brought back rocks. I explained to the home owner their line is broken and is in need for repair and handed her a bill for my hours work ($265) She had the option to hire me to locate the trouble spot for an additional $280. Or she can hire me for $3200 to make the repair. She knows a lot more about her sewer than she did before she called me. I and any plumber that sticks their rodder in the line should get paid for their time to diagnose the issue.
In Chicago if you do any rodding you do need to get a permit though. Its 10 bucks and all you do is call it in and they mail you the bill. There is no inspection when your done or anything. Its just so they have a running documentation of any troubles that home may have had with its drainage system. The suburbs do not require a permit for power rodding.