Broker commissions are always negotiable therefore, agents won't advertise their commissions because it can vary from one seller to the next. It depends on the type of home, condition, difficulty to sell, location, motivation of seller, etc. Commissions earned is private information which explains why there's no need to advertise our rates.
As for referrals, agents do depend on client referrals but that doesn't guarantee we will reduce our fee for a referral. We work hard for our commissions and a referral deserves 100% client satisfaction so a reduction would equal a reduction in services which is not something any agent is willing to sacrifice.