Only thing missing in the photo are drugs....but maybe they are inside the yellow bag in the background. 

So  a potential seller get a weird yellow mailer... 

In my “I will buy your house” marketing (yellow letters, postcards, etc.) for my investment LLC, I don’t disclose my status as a licensee, but I will disclose this during my initial conversation with a prospect even though I have no legal obligation to do so.You’re absolutely dead on about agents getting upset when one of my marketing pieces reaches the seller of a listed property and the seller contacts me, more especially because my marketing doesn’t include any disclaimer language.

It has an iconic yellow cover (even funny drawings).It is in the umpteenth edition now and often in libraries (free!!)

Second, it appears you feel low income stuff is impossible to manage and class A is the yellow brick road with zero challenges.

I much prefer a professional letter to a yellow letter but if you're set on yellow letters, I would keep it short and sweet.

Sort of like running a traffic light changing from yellow to red  - OK as long as nobody catches you doing it.

On averge, I get 15 yellow letters per month for each of my rental properties. 

They are veneer....which peels over time and also yellows. 

I own a nearly new home and I get yellow jackets on occasion.