I've said for years that the stop sign is counterproductive and in many cases inflammatory.
This, from a meeting between the NBA Players and Officials Unions.
"One of the actions discussed was referees giving the so-called “stop hand” to players during disagreements. While this is taught to referees as a way to diffuse a situation, it has been taken as offensive by players who want to have more of an open back-and-forth. Overall, the sides would like more open discussion of various hand signals and techniques."
https://deadspin.com/report-part-of-...%28Deadspin%29