Recently it has become viral that many experimental videos on how homeless people are more willing to give/share food with others than the general public.
This sort of no-chemical but emotional experiment on human beings ought to stop. Making such point is important, but not at the expense of the dignity of homeless people. It is dishonest to them, even if you paid them eventually for their unrealized role in your films. Though they are homeless, their time is still valuable.
The originality of this idea goes to those who were willing to get their hands and pants dirty. I've seen how they've gotten injured a few times in their "experiments". But the copycats are just nuisance with rebellious desires.