No. And I would hope that if there was some way of doing so (well, in theory, we could go in, change your password, then get into your account, but then you'd know something was wrong in that your password was changed), we wouldn't do that.
But observing the Who's Online list seems to be a pretty common tactic (personally, I don't find it very useful... but, meh...) so I wanted to point that out.