I have to say that I have never heard of a soft drink being included in breakfast along with coffee or juice. Agreed that it is considered an "inventory" item most likely, with no way for the breakfast staff to over-ride (comp) that. I'd be more inclined to mention it to the front desk afterwards to see if they would be open to removing the charge from the bill. "You can have that and 'one breakfast item' from the buffet" was, indeed, an odd policy. I recall that the Doubletree at Lloyd Center Portland used to be cold items only, with juice itself an a la carte extra without the upcharge/co-pay (coffee, IIRC, was included).