Twice, in the last month, I have been caught in unorganised multiserver queues. In one, long lines formed for each server, and people at the back jockeyed as they watched thelines move. Those in the middle simply were stuck in the queue they had selected.
In the other, people milled around until there was a free server, and by mutual agreement identified the leading person in the line.
Both queues could have been improved by the use of snake barriers, as used in theme parks and at many airports (but not in Madeira, the first place I noted). Surely these are one of the great inventions of queue management?