Increasingly, musicians and performers are making money on live gigs. And the only way they can accomodate the demand is by taking up bigger and bigger avenues. While some of the developed countries have high-end stadiums that are acoustically sound, most spaces are acoustically rather horrible - with echoes...
So as of late, It has become common to see Motorcyclists, Cyclists or Trekkers going out in groups on a ride or a trek. One of the issues you face is folks in the group getting lost - in the cast of cyclists and Motorcyclists its usually the signals...