Esther Inglis-Arkell in io9:
Instead of committing to intimidation, the scientists decided to commit to whimsy, and devised a weird, wonderful set of experiments with fake blind people asking math questions and police whistles distracting people on the road.
The police whistle made an early appearance in the series of experiments. A researcher simply sat by a road and waited until a person jaywalked across it. One loud whistle had that person spinning around, sure they were going to be fined or ticketed. When they saw the whistle being wielded by a civilian, they continued on their way.
But they found their way blocked by those most-feared of all street predators, the clipboard people. These clipboard people had a collection box and one of three spiels. The first spiel was a simple “Excuse me, would you please give me money?” The second was,”We are collecting money. Would you please give us some because we need to collect as much as possible.” The last spiel included an actual reason; they were collecting for a holiday camp for mentally disabled children. People who had been allowed to peacefully cross the road only got their wallets out for the last pitch. People who had experienced whistle-induced fear, then relief, were more likely to hand their money to whoever asked for it, regardless of justification.
Then the scientists decided to get theatrical. One of the researchers was outfitted with a white cane and a pair of dark glasses, so he looked like a blind man. They put him near the exit to a covered marketplace, watching people come out. He was to let four people walk by him, but when every fifth person emerged he was to dramatically grab their shoulder, because some experiments are conducted like jump-scares in horror movies. Once the innocent member of the public had jumped out of their skin and turned around, they saw a blind man. The experimenters thought this would fill them with relief. Half the time, that would be it — the man would apologize, and the unwitting subject would keep moving, only to be approached by more clipboard people asking them to fill out a survey about life in Poland.
The other half of the time, things got crazy. Once the person had seen the “blind man” and felt relieved, the blind man would ask them a math question. He would ask how many minutes he had until an upcoming appointment. Adding up the minutes in their head would cause them to re-engage their critical thinking, at which point they'd walk on and also be accosted by the clipboard people with a survey about life in Poland.
More here.