Choosing a Branch

Is http://quips-qt-io.herokuapp.com/quip-0005.html relevant in practise?

We divide the LTS into 3 periods:

strict: This period starts when the subsequent stable branch is created (for the 5.6 LTS, this would have been 5.7). Submitting to the LTS branch directly is then no longer possible;

5.9 is LTS, 5.10 exists, all types of changes are still submitted directly to 5.9. Not according to what is allowed according to the table from QUIP 5. Everyone has their own interpretations what goes where. Should gerrit not allow pushing directly to 5.9, or is QUIP incorrect?