... material may already be in existence, Jim, and not a plan to simply slab the material just for the sake of exhibiting a slab, which I would never think of suggesting the exhibiter breakdown such an assemblage... thus, a reasoning for "an exception to the rule."
As I noted in an earlier (related) post, the exhibit may be of a nature where reliability and genuineness would be necessary and essential to qualify for completeness of which all parts of the exhibit were to form a whole. An exhibit of such nature, of course, would probably be authenticated by perhaps the casino, a manufacturer, an historical society or a curator of a museum... and, as I also noted, this could also be under the direction of the owner of the material or even our club. Menetary value or grade may not even be a factor in such an exhibit... only rarity and historical value all slabbed by NGG or a similar company...
Again, such an exhibit would be "an exception to the rule"... and I would prefer our club exercise this thinking rather than a blunt... sorry, no slabs allowed in the exhibit area.