This is true. I'd not recommend any of this if you happen to live in one of the dustier climates.

I've got a spare ShopVac so I am able to dedicate one strictly to blow-dry duty. I am also lucky enough to usually have no worries over dust-content, so I have removed the filter from it as this reduces the biggest restriction to airflow. However, if you have dust or smoke troubles...one could leave the filter installed. It should remove most such contaminants prior to reaching the car.

...sT