Keep in mind that there is an element of subjectivity involved in the inspection process. A second roofer disagreed. Based on the two reports, the buyers and sellers were able to negotiate a satisfactory monetary solution to the problem for an amount that was in between the two estimates. It's problematic when inspectors are wrong. But it happens.
Inspectors are only human.
A home inspector looked at a house in the Oakland hills and issued a report condemning the furnace, which he said needed to be replaced. The sellers called in a heating contractor who declared that the furnace was fit and that it didn't need to be replaced. The buyers were unsure about the furnace, given the difference of opinions. So, the seller called in a representative from the local gas company. The buyers knew that the gas company representative would have to shut the furnace down if it was dangerous.