Synchonized jumping from bridges is a thing in Russia now.
It's new fun in some Russian cities, to jump from the bridge with the rope in a big group, when there is no water under the bridge but raw firm ice, also they use to jump at that same moment when the train is going thru the bridge -- just imagine what the machinist could think when he sees a bunch of people standing on the rails just before the moving train, so he probably starts slowing down and then all those people jump out of the bridge...