Here is a link to a description of the insurance coverage offered to troops and chartered organization. The troop must file and have approved a tour permit before embarking on any campout or activity for the activity to be considered “official.” As stated on the Patriot’s Path Council website:

A tour permit that has been filed with and approved by the local Scout Council prior to the activity registers the activity as an official Scouting activity. Insurance coverage only applies to official Scouting activities.

The Patriot’s Path Council’s page on tour permits has the best explanation of the reason for tour permits that I have seen.

Here is a description of the insurance coverage that is provided by the Atlanta Area Council.  Check the council’s website for the most recent description.