Can I ask how long that has been in the BKFA syllabus? I've been training since the early 90's, and the only time I've seen that performed was when I went to University in about 2001.
AFAIK when our club split (along with alot of other clubs back in the 80's before the whole gaurdians thing was set up) the only weapons were: Broadsword, Butterfly Knives, Tiger Spear (trident), and the knife/stick defenses.