Are things way different on Leviathan or something? I recently made an alt and leveled her to 50 on two jobs without an FC, and I got maybe 5 FC invites and 0 LS invites that entire time over the course of a month or so. I don't really feel like that warrants the time spent adding an auto-decline on FC/LS invites when you can already set your online status to 'busy' when you don't want to receive them. To date I have still never received a blind invite to an LS, and while on characters with no FC, I was never 'spammed' by anyone.