Shoutbox

Yes, it is possible, because as some said, Messenger does look for the DPs of people who are appearing offline.
But this method would be inaccurate, because AFAIK WLM does these checks randomly, you can't force WLM to check for people's DPs and it would only work for those who have set one.

As for the 'breach of privacy' argument, this depends on how you look at the issue. The data is sent from your contacts Messenger to your Messenger in any case, it just depends on what you do with this data.
I won't say you're not invading their privacy, because is some way you are, but for me it's rather a question of respect.
If you know this person is appearing offline, that he probably has his reasons for appearing offline, and if you respect him, you won't disturb him.

Same applies to conversation notifiers, you could say you are invading their privacy, but it again depends on how you look at it.
For example when my session notifier pops up (e.g. when WLM checks for a contact's DP (hint)) and I see that this person isn't online, I won't spam him just because I could.


Because this might have become unclear:
There ARE some ways to check if someone is appearing offline, but they are all unreliable / inaccurate.