On the standard (horrendously difficult to use !!!!!!!!!!!!!!! ) wheel adjuster arrangement it is possible to drop the screen whilst on the move but due to wind pressure it will not adjust back up from the fully lowered position without the feeling that it is going to damage the mechanism , thats if it moves at all.
This is no doubt due to a combination of wind pressure and the lack of mechanical leverage within the system has so god knows how well a motor will last without burning out or stripping its gearing