It's strange that people hang onto the theory of the "bot guy" placing order walls and then taking them away. Who is this mysterious "bot guy", is he alone and how many bitcoins does he have? It all sounds a little conspiracy theorist like. Anyone who has been around the share market for a while knows bids tend to clump around nice even numbers in penny stocks. There will be more orders at $0.10 then $0.09 for example. It's not a "bot guy" doing it, it's human nature. If there really is one "bot guy" out there with enough bitcoins to lower the price of bitcoins, then the whole concept of bitcoins is broken. One person shouldn't have that much power to set the price for everyone else.
The fact that the bid walls disappear as bitcoin's price approaches them is logical too. If you saw the price of a share plummet, would you stay at your old bids or lower them in anticipation of an even lower price? It's pretty logical.