Nice if that would be true... but... how would Messenger know that the user signed in from "another" location. What would be defined then as the "normal" location? It can't... As Matty rightfully said
here, there is no such thing as a "normal/default" and a "not normal/default" location as far as Messenger is concerned. This wasn't the case for older versions, and this is still not the case for the current versions. All it knows (and sends) is that the contact has signed in at _a_ location; it doesn't say if it is the contact's "normal" location.
What Matt from MD probably meant (and understood from your question) is that Messenger sends out information if the user has signed in from whatever other location at the same time he is logged in from somewhere else. This is something different than what you meant (
detecting if someone is signed in from "work" instead of his usual "home" computer, correct? Because then you would need to ask the contact first what his normal location would be).
This "
being-signed-in-at-multiple-locations-at-once" feature is called
MPOP (Multiple Point Of Presence) and is a new feature since WLM 9.0 (it didn't existed before that, and certainly not in 8.x). This is also what Matty explained
here in the first reply to your question. Also see the Messenger options:
Tools > Options > SignIn > Sign in at more than one place
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