Thank you for that Carmine. At least that's a logical solution and response to why those tests exist.
You're welcome vacmanuk. Same as showing a vacuum lifting a refrigerator and/or car. Old tricks of the vacuum demo trade that come and go. They resurface from time to time over the years by people who believe the hype. Even worse, the people expect others to believe too and can't understand why/when they don't. Even dyson recently used the old vacuum trick of picking up a car and aired the demo on European TV. Doesn't mean a thing. The operative question, like yours, is how many people use their vacuums to pick up cars?
Carmine D.