Seems to me like this is a perfect reason to have a contract for services. They pay you to do what is needed (or don't do if it's not needed), regardless. It simplifies the communication. You get to use your professional judgement. They pay a bill. Easy. From someone that has a farm, the nickel and dime crap gets old very fast. I go with the folks who charge a rate and do it (or not if it's not needed). As Yoda said, do or do not. There is no try.