I have figured out why some of you are unable to become inactive on Trillian.
YOU MUST USE: "Sign Out" and NOT exit when you leave Trillian. I am not sure about PC users, but it definitely works for Mobile Users!
From my own experience I believe it doesn't matter for PC users. BUT I watched someone disappear from a "Mobile" status when I told them about this. Try it and see.
Simone