I can see if you clip the clasp to the stationary ring then it won't slip, but would be like a normal collar. The site instructions say to clip the clasp to the 'floating' ( moveable) ring and the lead to the stationary ring -in which case it will become a slip lead.
It is buried, you have to read the whole thing to find it, but they dog (oops, do )say you can attach the clasp/snap to the stationary ring. "3. Attach snap to floating or loose ring." OOPS on me, no they don't. Most of us would think of this ourselves though.
On your link to the Volhard article though they specifically say to attach the clip to the floating ring - that makes it a choke collar. The vast majority of dog owners will follow the instructions of the manufacturers - after all aren't they meant to know how to use their product?
