The whistle is a good idea, in Boy Scouts we have taught that the use of a whistle usually means trouble or someone is lost. This is a signal with three....med blasts. I use it to assemble the troop. As far as yelling at the scouts...it has a time and a place...when no one is paying attention...usually not yelling just a loud "SIGNS UP" and that gets their attention. When we have a scout or scouts that are out of control there are warnings given. 1,2,3,up to 5 we use the chain of command rule, patrol leader, Patrol leader and Senior Patrol leader, Patrol leader, Senior Patrol leader and Assis