Species -- classified by taxonomists from populations of wild plants.
Hybrids -- crosses with other species or hybrids (mixing of genetic material between species and/or other hybrids).
Cultivars (Cultivated Varieties) -- selections by humans from species and/or hybrids (see above).
I have heard talk of destroying seed produced by cultivars *[IMG]http://www.**********.com/iB_html312/non-cgi/emoticons/rock.gif[/IMG]
As long as proper notation is used to refer to plants produced this way -- I see benefit rather than any harm. Only possible negative impact I can see would be not to keep track of the true status of these plants and to intentionally or mistakenly give them their parent's name; i.e. You self pollinate Pinguicula 'Sethos' and then label all the F2 progeny as if they were the same as their parent, Pinguicula 'Sethos'. This would, in most cases, be inaccurate -- to say the least. See photo of population of Pinguicula 'Sethos' x self seedlings below:
As can be seen, these plants are apparently doing what they would be expected to do --- they are segregating. In other words: the genes they inherited from their grandparents are being reorganized into different patterns, producing unique individuals. Some of these individuals may deserve cultivar status of their own. . . but if I had destroyed the seed produced by their parent, then, sad to say . . . they would not even exist.
This is a very normal process for subsequent generations of plants from hybrid origins, that they swing back and forth between the characteristics of the original hybrid parents, until, sometime in the future, conceivably they could stabilize into various populations of plants with similar characteristics, i.e. artificial species. Don't forget to consider some of the possible complications this process may include: self-pollination, crossing back to one or the other original species, crossing between other survivors of the various generations that may bloom at the same time and that have compatible pollen. I believe this is where the term "hybrid swarm" comes from.