Furnace Ducts to bedroom Crushed by Blowout

We learned about dangers of old but new looking RV tires when a flailing steel belt ona rear dual wiped out wiring and cracked the holding tanks. Spent a weekend in a seedy Puyallup, WA RV park waiting for the RV Doctor to open and plastic weld the tanks. We learned later about front flexible brake lines blocking up inside and causing sudden hard pulling to on side on appliaction of brakes. Old rigs may have special dangers for unwary newbies.