I looked through our Development write-ups, but I didn't find any mention of that particular behavior.
The standard out of the box default installation of AutoCAD MEP has defpoints color 140... see all of the installed templates at C:\ProgramData\Autodesk\MEP 2013\enu\Template
I checked all of the AECB*.dwt files... every one of them have Defpoints layer color set to 140.
After checking with other Development and Support resources, I found that:
Thanks for the explanation...
I fully understand that you can do what you want with templates...
My practice with a new release is to always create new company templates from out of the box templates. The users were asking why I changed the color of defpoints. I did not change it .. so I investigated.
Side note: I know probably 90% or more users put viewports on defpoints layer. In my oppinion, it is better practice to let AutoCAD use defpoints and refrain from putting any other objects on it.