Eventually a cheap money policy can quickly become a funny money policy, but on top of it QE1....N creates money ex nihilo creating demand for securities in two ways. Quite directly because the Fed is actually buying assets and secondarily because the people that are selling the assets to the Fed now have cash to buy more securities.
Abstaining in the face of perceived risk. I don't know if a roulette wheel will be red or black. If I play, I'm gambling and its inherently a gamble. Likewise, if from his individual point of view, he doesn't know (with any degree of certainety), individually he would be choosing to "gamble."