So you say you are going to do a free CMA on their house because:
1) The person very well may want to sell their property.
(o.k. - that's the main reason people ask for one at which case agent will do them... because they are trying to get a listing)
2) The person may have friends or family who want to sell their property, or who want to buy property.
(nope. Why would an agent do this? More likely in this situation the actual conversation would go something like... I'm not interested in selling my property, but my friends or family might want to sell or buy property: and you as an agent would say: Well, so I should speak with them.
3) The person may want to sell in one, three, nine months or in two years. They very well may call me rather than look in the phone book at that time.
(o.k. again there is an expectation of getting to make a listing presentation. If a consumer said to you... I'm not looking to sell for nine months or two years... you're going to do a formal CMA only if you expect to be able to make a listing presentation in the future.
4) The person may want to buy a rental property.
(so the reason for doing a CMA on this one is why?? to see how much equity they have?? If you did a CMA then there is an expectation that you want to be considered for helping them find rental property.
In each case there is an expectation of potential business in return for service.
So if you think you can get a CMA for free from an agent without an expectation of potential future business... and feel that it's your right to receive one and expect agents not to solicit you for business.. you need an ethics lesson.