In the FAA's ACS and the PTS there are many references to preventing runway incursions. In the test standards one will find it is elevated to becoming a special emphasis area and within the CFI PTS, the mandatory runway incursion task is the longest and wordiest task. So clearly runway incursions is a special subject for the FAA.
I understand the safety importance of this, but what strikes me as odd is it seems there is too much emphasis on this subject. Most of the mentions are added as revisions of the text. Reading between the lines, did something like a specific incident cause these additions? Was there an emerging runway incursion trend that prompted this?