Have your husband show you the factory UL and NEMA approvals for duct tape on the drier vent. The factory specifications give the cues for the determination of local code. He could also show you all the homes that use duct tape regularly on dryers and furnace chimneys as part of the installation manual. The approvals are how the insurance company and local code officials determine faulty equipment after a fire or carbon monoxide poisoning has done their damage. Getting away with a bit of everything is a way of life; he did save at least ten bucks. Clip more coupons to pay for a new hose and you could be safer; but then you couldn't afford that one night out at MacDonald's.