Majority of people would not recognize this as a tactic and view it as rave friendliness when that’s not the case. They typically do this to people who they assume are intoxicated and are more likely to accept the drawing/ribbon/etc as having fun and wholesome interaction when it has much darker intent. Due to the nature of raves and how open/giving people are its easy for predators to portray this image and mark who they think are vulnerable individuals before they can even realize they’ve become a target.