Quick side story, related to the topic.
I just had my first meeting ever, where I planned on having 10 boys and their parents, and one mom unexpectedly brought along a younger brother because she had no sitter. I was a little worried at first, since I only had enough juice boxes for ten boys due to my inexperience in planning for the unexpected. Nevertheless, I included him in everything, from the snacks on, and it was great to see his face light up when his brother made him a friendship bracelet just like all the other boys got. I did this because I remember being too young to be a cub scout, and having to sit at the meetings and do nothing while my two older brothers got to have all the fun because my mom had nobody to watch me during the meetings. And thirty two years later, I still remember how heartbroken I was to be excluded.
Also, more to the topic, we're having our first Pack Camp Out soon, and it is made blatantly clear that every parent and every sibling is welcome to come, from the Boy Scouts down to the Tiger Scouts, as long as the parents understand the Leaders aren't babysitters and that they are all expected to be involved and take part in the activities. It's all about creating a positive enviornment for the boys AND their families.