Most frags are made by cutting the coral not the frag. Also, when I frag a coral it is a colony. Not a frag that I bought with 5 polyps that I'm trying to make a profit out of by cutting into even tinier pieces. But I suppose your right. If that's the business plan I suppose cutting up the frag plug would be necessary for that type of coral.
Also maybe it's just me but I wouldnt sell or buy a single polyp.
Most Corals Yes, you cut the coral (Favia, Acro, Hammer, etc.).
We are talking about Zoanthids here.
Cut through a Zoanthid Polyp.
It is not going to live.
The Proper way to Frag Zoanthids is to cut around Polyps (Best Done on a Frag Saw).
So you cut the Plug or Rock and Glue that Surface to a Frag Plug.
I see some people taking Razor Blades to "Sliver off Polyps"
That is Very Unprofessional.
They are Softies and can Easily Detach if you do that or a Snail Could Knock them off.
Glue touching the Flesh of the Zoanthid will Irritate them.
Gluing a Plug or Rock or whatever Hard Surface the Zoanthid is on to another Hard Surface is the Only Safe and Proper way to Frag them.
This goes for any Sofite not Just Zoanthids.
Try Gluing a Mushroom Polyp to a Rock or Plug and see what Happens.
It will just Detach and go to the back of your tank and most likely shrivel up and die.
For LPS and SPS you can cut the Coral and Glue it to a Plug but not Sofites.