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Arguably the entire purpose of having a RE License is to protect the right to commissions and the NAR's intent (National Association of Realtors) was to protect the right of brokers to this compensation.

I believe US real estate agents are not required to be members of the National Association of Realtors (NAR) though if you want to market yourself as a Realtor you must be since the word is trademarked.For a long while most full-time agents who worked in the residential arena joined because it was almost a monopoly, but times are changing. 

Keep it fair and transparent, letting everyone know the deal details, and make sure everything follows the rules.Utilize resources like the National Association of Realtors (NAR), local real estate groups, and real estate lawyers.

Look at NAR reports - you can see what properties list for and close for.

Check out occupancy using NAR data.

If they also do real estate sales, they will almost certainly belong to NAR (National Association Of Realtors) and their state's association will provide them with well vetted forms conforming to their state's laws at no additional cost.

Leases: Georgia NAR (they call it GAR) actually has standard forms written by lawyers, used by realtors.

My wife & I attended the NAR National Convention in SD,CA last year.

Today I have become a member of the NAR and the GAR as well as the Athens board of realtors.