[sjadoinqwoeihad]

Yes 100%. This reminds me of bees or fireflies. They have algorithms that individuals follow which can cause the collective to behave in a certain way. We should definitely create something like that.

You can't rely on spoken signals, mainly because of other noise and broken phone effect. Something like raising your hands and crossing them could work. People who are close to the crush will quickly agree and raise their hands, so it's unlikely that one troll could make a false alarm since you would need maybe ~30 or so people to get the signal started. This signal could propagate through a huge crowd in just a minute or two.

Initially I thought about drones with arrows and loudspeakers but it seems a bit too niche of a usecase to have a swarm of drones for. Also doesn't quite work in all conditions.

I had a lot of mini crush experiences in primary school. Students holding doors for fun and everyone trying to push through. People jumping on top of each other and making human piles. I think these are all good experiences to understand how crowds work, even at small scales. I think schools could teach this kind of protocol and practice it. It's also important that this doesn't cause a mass panic and a stampede so drills are necessary.