As inevitable as razor blade manufacturers adding another blade to hype a new product, news of 4D on the horizon.
As with 3D, its not a new idea; there were experiments with this in the 1950s!
I've seen '5D' cinema vans/trailers at a seaside resort in Latvia too (3 years ago).
Will this take off? Eventually, I'm sure it will, but not until costs drop significantly...