It comes down to did you have a contract with the client to find those kinds of problems?; and if you did, did you miss it?; and if you did miss it, did the client suffer an economic loss as a result? Some inspectors are advertising a $5000 home inspection that tests every switch, door, window etc, removes every cover removable, and documents every visible thing in the house. They never sell one, but the client reliazes that what they are getting isn't that!