I understand that more than likely linden labs will proceed with the disabling of detecting if someone is online or not through scripts. even though it will break many systems for club owners, builders, and delivery systems. I just hope they have it figured out how to market sl to people who will be paying customers once they tick off most of there paying customers with all these "proposed changes", which seem to benefit people who want privacy for there avatars.
While i see why people have a wish for privacy, i for one only check if someone is online if i have reason to. maybe i am wrong but if people really have a wish for privacy, shouldn't alot of changes occur. the ability to view through prims needs to be removed, wireframe removed. ability to "look" into sims revoked. the jira issue was due to being stalked, and if the stalker knows where you are in sl, they can look to see if you are online or not. never mind hiding if your online. unless like others have said, you have neferious reasons to do so. which case, again. make an alt, and don't have friends on the alt. and your problem is solved.
I would personally love to see the RL setup of the people who are so concerned about privacy. they must live in a building with no windows, a steel re-enforced door, all fully sound proofed and thermally insulated. all behind 40 foot cement walls around there property.