Here are relevant references from the Books where the leash as a whip is mentioned.
I make no pronouncements on these matters, but report them as I find them.
Arrive at your own conclusions.
I wish you well,
Most slave leashes are long enough to serve not only as a leash but also as a lash.
Magicians of Gor Book 25 Page 195
When one leads, as, say, if it might be the wish of the rights holder to so display one, one might, if one does not, for example, walk well, feel the free end of the leash only-too soon, as a lash.
Witness of Gor Book 26 Page 162