Builder Solicitation

Two of my clients, whom I have their house listed have received letters from builders saying they will sell my clients home for free with another Realtor if the client buy one of the builders homes. They said they have made a deal with a group of agents to do this. This is just a backhanded way around the CODE of ETHICS by some Realtors-in my opinion. The builders said they would not disclosure the agents names but told me the homes would be listed on the local MLS and Realtor.com. The agent would then represent my Sellers as Buyers agents . My clients ask if I could represent them and they said no. Why do you think about these agents and builders.