A very good point and this is a different twist to its use. I suppose I was thinking in my OP as using undeveloped but exposed film as in the same way a musician may use silence within their music, or perhaps a film maker may run a sequence of black within the story of a film. I think to use this concept effectively in exhibition, it would perhaps need to be placed at the end of a series of displayed (printed images) on a very specific theme with the undeveloped roles/cassettes identified as a continuation of this theme. In that way it would leave the viewer of the displayed prints asking questions about the content of these in relation to any artistic development shown in the final image on display, as I believe someone mentioned an unfinished symphony.
With regard to my last post, I also think this would have more relevance done with slide film with the images viewed by transmitted light in display. This then negates any printing techniques and has more relevance to an unprossed roll of slide film.