Final answer:
If brokers agree not to co-broke with a discount broker, it is called anti-co-brokering.
Step-by-step explanation:
If brokers agree not to co-broke with a discount broker, it is called anti-co-brokering. This occurs when traditional brokers refuse to work with discount brokers in order to protect their commissions and market share. Anti-co-brokering is a common practice in the real estate industry, where traditional brokers may view discount brokers as a threat to their business model.