I heard the same thing about the yellow hackle; that it represents 100 years of shame or something of that nature.
Other urban legends:
1. The girl who walks into the Junior Ranks Mess who is very pregnant, looking for her boyfriend "Carl Gustav".
2. I heard about a JNCO course in Wainwright who were spending a week in various defensive positions and, deciding that they didn‘t want to dig the trenches themselves, put in an Ad Rep for a digger (that Engineer Trench Digging Machine thing whose name eludes me). Apparently, the course staff, being the sadistic b@stards they are, managed to get the vehicle out to the field, ready for use, and then asked the troops, "Which one of you is qualified to operate this?" None of the troops could, and so they had to watch the thing drive out of the field again.
3. During WWII (not sure exactly when), apparently a patrol came across a stick of British Paratroopers dead on the ground, with their parachutes still intact. Apparently the static line broke in the plane, and they all died on impact. I don‘t think the Brits used reserve chutes in those days.