pre purchase inspection

Unless I had complete knowledge of an RV I was buying a pre-inspection is very important by a professional. That said, how do you rate that professional? When I bought and sold rental property I saw a lot of so called professional home inpectors. One that really comes to mind is an inspector that told the buyer I had a dangerous fire hazard with AC electrical wire laying on the ground in the crawl space under my house. I pulled all the wire out and it had to be inspected again at the buyers expense to allow the house to close escrow. What was the wire? It was heavy duty shielded 300 ohm TV lead in wire from the TV antenna. Bottom line. Make sure your inspector knows what they are doing. At least they can tell the difference between a generator and the engine that powers the RV. :B I'm sure there are good inspectors out there. Also some losers posing as professionals.