Good customers need to be trained! There's a lot of stuff you need your teach customers so they can be good customers:
Real estate photographers typically don't do a good job of training customers on #4! Cal in Charlotte, NC told me today, "one agent customer thinks she owns the photos and refuses to let new listing agent use them. I can overide her, but at risk of losing her (and rest of firm's) business!" These kind of misunderstandings are very frequent!
Here's the underlying problem: most agents have zero understanding of photo licensing. The concept that you pay several hundred dollars for photos and you only get to use for a limited time, and a single purpose is completely foreign to most people. There's very few other products that work this way. So the concept of photo licensing needs to be carefully explained to agents and you have to make sure they understand.
I recommend that real estate photographers have a simple one page terms of service statement that explains their terms of service including their photo licensing policy and before the first shoot have a discussion with the agent and ask them to initial the terms of service. No need to initial again unless it changes. But by having a written TOS and taking the time to explain it to all customers you save a lot of potential confusion and misunderstandings.