All airlines are doing this now -- probably related to fuel costs. Past experiences of agent generosity in exceeding baggage allowances are simply not applicable to today's environment. An interesting point in your original posting is that the computer was not allowing the agent to accept the baggage without the addcollect for excess. Lots of airlines have revised their computer systems to enforce the baggage limits, removing the agent's discretion in making an exception. BA is somewhat more militant than other airlines about this, for various reasons, but all 3 alliances are doing this same baggage enforcement.