Welcome! This forum has a treasure trove of great info – Scouters helping Scouters! Just a heads up, though - all content, information, and opinions shared on this forum are those of the author, not the BSA.
If a scout is marked as dropped/opted out, desired behavior is that they no longer get any correspondence from the pack. Both anything that was previously scheduled AND anything that gets added in the future until Nationals drops them from my roster.