A metro carriage is close to the ideal case for a Bluetooth mesh. A few dozen radios inside ten metres means every hop is cheap and nothing waits long for a repeater. The catch is that the same density saturates a flood mesh, since every device rebroadcasts to everyone it can hear. So the peer count in the channel says less than whether messages still got through once it filled up. Did it stay usable at that density?

It's interesting to see digital channels like Bitchat becoming a hub for real-world organization. Does the ephemeral nature of these chats influence the spontaneity or coordination style of the demonstrations?