I have been writing before about the take-over of my subways stations by a weird combination of Greenpeace and Ford.
What is happening now in the Greenpeace corner of this subway station is an excellent example on how spoofing is spilling over from the internet onto billboards. Here you see three examples.
I'm not sure how the lawyers of Sanyo and Sony would think about this creative way to get attention for the environment. Tactically the best way is of course to shut up, but I do think these billboards have been made to provoke a reaction, especially because the companies involved do not seem to have that bad of an environmental reputations, only a nice logo that is easily used for other purposes.