The Plumber said to ask about your O&E insurance

The Plumber said to ask about your O&E insurance 

I did an inspection for a nice couple a few months ago. They moved in and have been very happy with their new home. Now, that trhe weather has gotten cooler, they noticed that there was a noticably cooler part of the house.
They called a plumber to check the hot water heating system. The plumber found a radiator in the kitchen, under the cabinet drawers in the kitchen that wasn't heating. So he took the drawer out ,breaking the bracket off while doing so. Then he took the bottom of the cabinet out to find that there had been a fan behind the radiator to help circulate the heat, that had been taken out.
He told the couple that it would cost them $450 to replace, and the inspector should have cought this on the inspection, so you should call him and ask about his O&E insurance.
I recieved the call and went over the same day to see how I could have missed a whole section of the home not getting adequate heat. The couple is older and I did not want them to be cold.
By the time I arrived they had already found the problem. They simply had to turn the thermostat up for that area of the home. The heat was fine without the fan that had been removed.
It upsets me that an incompetent plumber taking advantage of an elderly couple, blames the inspector and starts giving legal advise.
The home inspection is non-invasive! This means I don't take cabinets apart (and if I broke them taking them apart I would certainly repair it).
In the end the couple is cozy and warm,no insurance claims, I didn't charge anything for the house call, I don't know what the plumber charged but at least he isn't getting another $450.