I find that the whole issue with scouts (or other church related activities) and people being flaky comes down to one thing: Priorities. The same parents who back out of a scheduled day or two at camp would NEVER back out of that football game or that basketball game or that baseball game. They would find a way to take work off for those events but easily find excuses to get out of camp. It really comes down to priorities.
Shouldn't their son be the biggest priority regardless of the activity? Just saying. Go ahead and flame away.