I suspect there may be a bit of speculative buying going on myself. If I were feeling a bit flusher I too would've been snapping up anything red as soon as the the Con Shads were announced, with a view to selling them on as interest in the

's grew, and hopefully peaked around the Convention time and slightly after, once folks have read about the Red Shadows in the convention comics.
There will also be a bit of panic buying from the collectors who want to keep, and have been meaning tobuild up their Shadow armies for a while, but now fear the price rises, and so are currently bidding high and trying to get in before interest heightens, but in doing so it is almost a self fulfilling prophecy.
And there you go - my first use of the word "prophecy" in a thread!