Talked to a parent of a Boy Scout this weekend. He did not touch this topic and indicated that his son would continue with Scouts. I wonder if a lot of people on the local level will just assume that this will not affect their little troop, which is filled with people they already know.
And when something happens to their son, what will they say? Willful blindness.
I believe a small number of boys in scouting will continue; especially the ones close to Eagle Scout who have worked hard towards that goal. The real drop off will be in the younger scouts where parents will find alternatives.
Also, as boys get older they tend to drop out of scouting anyway. I suspect parents who would have previously encouraged them to continue will just allow the boys to leave scouting with no protest.