Hi Geo
not too sure if the idea for KBAs has changed but in my understanding they were never meant to replace documentation or to provide complete topic overviews.
Given the nature of this alert, it would be weird to
a) get an alert at all for this
b) have someone reacting to it.
The function to unload containers after they haven't been used in a long time is part of the garbage collection in SAP HANA. Why would it be necessary to have an alert for that?
And then what should anyone do about it? What do DBAs usually do, when long unused data gets displaced to disk?
Exactly: nothing 
Concerning my remark about SCN usage of SAP employees: I meant that there are plenty of SAP internal forums and communities available where you can probably get less exposure to the rest of the world and might get answers that provide you with more detailed information than what is possible in SCN.
As English is the corporate language and used in SCN as in the internal forums I don't see how that is an obstacle for using the internal forums.
About your unanswered questions: just like any other forum, SCN is based on voluntary contributions. There should be no expectation about how long it takes to get answers.
Nobody is paid to answer the questions here, so it's all on a community basis.
- Lars