If you just drop the trash bag over the filter then duct tape around the filter but over the bag it should be tight enough. Once the bag is snug against the filter body it won't fly off. I suppose the reason someone stated not to tape to the body of the filter is because duct tape sticky goo can be a dog to get off after a period of time although gasoline can be used on the filter body to clean it off without doing any harm.
Al