Agent/Direct Mail ethics

[Lee S.]

I'm currently waiting to get my application processed to take my test in RE Agent test in California.  I'm becoming an Agent to benefit investing and I only plan on listing properties when the opportunity arises.  

My question is regarding direct mail.  I know ethically it's not ok to approach homes that are already listed by an Agent, i understand that and respect it.  However, I plan to do direct mail and i'm sure my mail will end up in some mail boxes of listed homes.  I'm hoping the answer to this question isn't to go through the list and mls and remove all listed properties.

Is this something I shouldn't worry about since it's unavoidable or should I put something in my mailer that states something like "if you are already listed with an agent, please disregard"?