well the 'Ambassador' tag could have connotations...

and i can see Companions being used as spies in various ways; pretending to be whores, gathering info - spying on the alliance officers collecting gossip and so forth, on plans, rivalries, character and so on.

i've never given it much thought before but there are possibilities if you look at the Civil War and the disputed neutrality of the new Orleans bordellos, and France during WW2 and so on.