I really don't know much about that side of law, but I can't recall hearing of a case where an individual in a company can be taken as a contractual binding agent in all cases. eg. Could I phone up a BP salesperson, ask them the price of shares, and if they say 'You can have the company for a dollar' that the entire organization has to honour the agreement that one employee made? Somewhere there has to be division between corporate responsibility and individual responsibility, I'd have thought, so that a company isn't bound to whatever mistakes single employees could make.