The workplace is a typical example: the employees below a middle manager are in his in-group and may be spoken to using casual speech. His bosses or even, in large companies, people in other departments, are in an out-group and must be spoken to politely. However, when dealing with someone from another company, the middle manager's entire company is the in-group, and the other company is the out-group. Thus, it is acceptable for the middle manager to speak about his own company, even his bosses, in non-honorific speech. That emphasizes that his company is one group, and although the group may have subdivisions inside of itself, it does not include the other company.