1/ Did Charlie Munger say this?

"Can you recall when a promoter bought a stock that was more than 100% shorted and was able to convince many people who didn’t know exactly what to do that if the promoter was buying that stock then it was a good idea for them to buy the stock?"

2/ Not exactly is the answer. Munger was actually using the example of oil company CEOs buying fertilizer manufacturers to illustrate "bias from over-influence by social proof, that is, the conclusions of others, particularly under conditions of natural uncertainty and stress."

3/ Cialdini: "We will use the actions of others to decide on proper behavior for ourselves, especially when we view those others as similar to ourselves. When we are uncertain, we are willing to place an enormous amount of trust in the collective knowledge of the crowd."

4/ A promoter who wants to take a stock up to corner hedge funds who over shorted a stock will use the techniques employed by the compliance professional who invented the Tupperware party.

Buffett: "The five most dangerous words in business are: ‘Everybody else is doing it.'”

5/ To avoid dysfunctional bias from social proof and other human bias Munger suggests that you first consider the decision rationally and after that apply a check for human misjudgment.

"Am I making this decision to buy GME because other people have made the same decision?"