A properly executed Boy Scout program[1] should give adolescents a lot of unstructured time and leave them with the sense that they spent a weekend hanging out with their friends having fun. It's only at the Cub Scout level where it's appropriate for adults to be planning and leading a highly structured weekend of activities. When I take my troop camping, even if there's a fixed plan for an activity during the day (eg. if we've hired a whitewater rafting outfitter for the day), by 4 or 5PM on Saturday we're back in camp and the scouts' time is their own from then until mid-morning Sunday when they need to be packed up and ready for the drive home. They're still loosely supervised by adults, but there's no adult telling them when to start cooking dinner or when to go to bed.

[1] The program is officially no longer known as Boy Scouts in the US, now that it's starting to go co-ed.

For cub scout camp directors, the plan must include daily scheduled periods of 'down time' during which scouts can play on open fields or playgrounds. For a four hour/day camp, this might be 30 to 45 min in the middle of the schedule. There's also free time before and after opening and closing ceremonies. The same is generally advised for meetings. Before a meeting, it's best to give them some time to blow off steam before having them sit for any length of time for anything structured. Making things fun is the best first step toward not only engaging them as individuals, but getting them engaged with each other. So yea, essential and well recognized by experienced scout leaders