I've found a bell works the best for pedestrians, "on your left", of course, for cyclists. Nothing work with a hooded, iPod-wearing ped. As far as kids on bicycles are concerned we just slow way, way down. We're on a tandem which is not as maneuverable as a single and could cause a lot of damage. We wave when we go by and the kids usually get a kick out of the big bicycle. We generally just do a 14 mile section of MUP as a change of pace, early in the am, and don't encounter much traffic.