Answer:
The seller must be properly informed that such a policy may result in market exposure or collaboration from other brokers being limited.
Typically, commission splits are transmitted through a multiple listing system to other brokers when determined.
In the lack of a multiple listing system, commission correspondences or broker-to-broker agreements are a standard way of agreeing on terms of commissions for sharing.
Most conflicts can be prevented if the terms of commission sharing are agreed well in advance and communicated clearly to prospective cooperative brokers.