Despite the prohibition on driver-activated aerodynamics other than the DRS, Mercedes have themselves a DRS-activated F-duct ('fluidic switch'). It seems that if a fluidic switch is activated by driver-activated DRS, then that fluidic switch does not constitute driver-activated aerodynamics. Curious.
Speculation continues, however, about the exact purpose of Mercedes' F-duct. There are slots in the undersurface of the front-wing, and Craig Scarborough suggests that the purpose of the system is to blow the front-wing.
Here's another possibility, however. One of the advantages of the active-ride Williams FW14B was that it reduced drag in a straight-line. Here's how:
"We realised in the wind-tunnel that if we lowered the rear and raised the front, you could stall the diffuser and that reduced the drag of the car significantly...I can't remember the figure but that would give them something like an extra 10 kph," (Adrian Newey, p233-234 in Williams, Maurice Hamilton, 2009).
So could Mercedes be stalling the diffuser somehow? The diffuser downforce depends upon the vortices which peel off its lateral edges, hence if one could blow these edges, one might be able to stall the diffuser.