No not really Iv never used it TBH and never attemted to, but i can remember reading/seeing it some time ago, and though if i drew it, it might jog Neon's mind
The way i see it, is that the top swivel will pull free on the take or the strike, just leaving the bottom swivel in and if the lead snags the only way for the lead to go is off backwards, (if i remeber correctly both swivels have to fastend to the leader)