Hippie Epistemology

A strange group of people interrupted the thesis writing at my favorite local coffee shop.  Sometime after they had finished setting up dozens of tea lights around the stage, I wandered back up to the front of the coffee shop for a cigarette.  Forced to pass by the table they had turned into a checkpoint to stop everyone passing into the back of the coffee shop and accost them for a "donation", I glanced down and read the following "warning" on their flier: "Be prepared to rethink some of what you already know."  Obviously, their performance was going to be detrimental to my epistemic health.