Of course a customer can exert control over the pilot he is paying. He can tell him where and when to fly, when to stop, what to photograph, etc. 7(b) doesn't say that that the customer needs to have total control over the operator: only that he should not have zero control. Therefore any measure of control means that the pilot need not be classified as a commercial operator.
If you are not familiar with this definition, perhaps it is new?
That approach was tried by the military during the operation of drones in a war time environment being operated by civilians. The military "Mission Commander" laid claim to being the Pilot in Command and ordering civilian contractors to perform certain duties that turned them into "combatants" under international law. It worked out that civilian operators could be tried in an international court for "war crimes" that might have been committed if they complied with the orders of the Mission Commander. By complying with those orders, as the legal pilots in command, they opened themselves up for war crimes prosecution. The only legal means for them to remain a non combatant was to refuse the order and/or remove themselves from the operational environment and command and transfer control of the aircraft in the current operational environment to military personnel. A shorter version of all that is that anyone manipulating the controls of an aircraft is the PIC, with very few exceptions, and all of those have a flight instructor or another qualified pilot present to assume command of the aircraft during a flight emergency. As an example, someone flying a helicopter on a movie set would be taking orders from the movie director. The director is in no way the PIC as only the PIC is capable of establishing that such directions are safe to execute and that the aircraft is capable of such execution, which in turn allows the person at the controls to accept or reject the director's orders. An event that set that into history killed the actor Vic Morrow and several others. The person at the controls is PIC.
In the U.S. there is FAR 91.3 that specifically states the Pilot in Command is the sole authority for determining the outcome of a flight, and is authorized to exercise any and all steps needed to assure the safe outcome of a flight, including rejecting instructions from ATC or any other source if the PIC deems it necessary. In full scale aviation where fatal accidents have occurred where two pilots were at the controls great effort has been expended during autopsies to establish which pilot was on the controls at the time of the crash to establish exactly who was the pilot in command at the moment of impact. Aviation law is very clear that unless it is an instructional flight where a flight instructor is providing instruction, or when the flight is being conducted in VFR conditions with the person manipulating the controls using a visual restriction device under the supervision of a safety pilot not visually restricted, the person handling the controls is the PIC. The PIC makes every decision relevant to the operation of the aircraft, not anyone else, ever. In the situation previously described where a client is telling the flight operator what to do, the client is an advisor, not PIC. The person flying the aircraft maintains ultimate and absolute authority over the aircraft at all times.
As for hobby insurance, it's quite clear when people read the fine print of their hobby policies that the moment consideration is obtained from the flight it becomes a commercial application and hobby coverage will be terminated. I'm not a lawyer but I know full well insurance policies are written by lawyers and they make it a point to cross all the "T's" and dot all the "I's" where money is concerned.
What I am seeing as this thread progresses is another business person trying to avoid obtaining a commercial license while also trying to use drones to promote his professional interests, and in the process reaching for any minutiae in legal documentation that might provide him/her the means to operate commercially without first becoming a licensed professional. Point blank, if someone takes their clients out to look at cell towers using a drone they are acting as an aviation professional. The use of the drone is flagrantly commercial in intent. At
minimum they are using a drone to advertise their business, clearly a commercial application, and attempting to thwart the law to avoid meeting appropriate licensing requirements. Some might call it seeking a professional advantage. To me such an act does not reflect well on the business person's decision making as the cost of obtaining a commercial license is far less than the cost of a decent camera drone, and the fines, or damage awards after an incident, far outweigh both the cost of the drone and obtaining a license. It would not be surprising to see a company's liability carrier cancel policy coverage if they learned their insured was operating drones illegally. Some commercial carriers have already made it very clear they won't even cover those operating them legally as they don't provide coverage for aviation incidents of any kind.