So...
In the other thread started by
wanja that mentions some NBA sites with ref's pictures (
http://forum.officiating.com/showthread.php?p=519403), there is a link to
http://phillyref.com/basketball/nbarefs/nbarefs.html.
In this thread, BBR and Nevada discuss the legality of posting rules online. The PhillyRef site links to
http://www.mtboa.org, which has some videos meant for instructional use, presumably for beginning officials. One of those videos, the first one listed, discusses the block/charge/screen. The first discussion point in this video is LGP, and the discussor eventually gets into the defense being allowed to move, and also discusses the airborne A1 and B1 moving over laterally, trying to maintain LGP. This is seen at 1:30 into the video.
Even this guy says it's a block! And he claims to be only refereeing for 3 years.
