There are other high pressure sources. The reason mercedez chose the RW DRS is because they only want the front wing to "stall" during DRS usage. They could have routed pipes from any where else but it just would not activate in a controlled manner.
Lets say we duct the endplates as suggested, what is the plan?
"I was blessed with the ability to understand how cars move," he explains. "You know how in 'The Matrix,' he can see the matrix? When I'm driving, I see the lines."