I ordered seeds from albermarelsounds on reccomendation from a TF member who had great germination. I don't believe any of the species of the 5 I ordered were even rare. I've seen all of them for sale commonly in stores and on eBay. I don't support poaching in any way and I didn't know the seeds I ordered were poached at the time I ordered them, but in all honesty, I don't think a gymnamphora, glabrata or tentaculata is going to become threatened any time soon. By selling the seeds on eBay to people who will closely monitor them to make sure they get as high of a germination rate as possible, it may actually be helping the species in general, not in the wild. If something were to happen to where the population declined, there would be thousands and thousands in captivity to help preserve the species. They aren't going anywhere with all these hobbyists. Also, neps are like weeds when given optimal conditions. When given those conditions, they will flower and create thousands of seeds. Not all will survive, but I think a lot more seeds are being produced than poached. The market for nep seeds is so specific that there would be no reason to collect lots of seed pods, because not that many will sell.
That being said, collecting seeds from the finicky species that may even die often in the wild, or species that don't breed as much, or species that are very scarcely found is probably a bad idea. If I see seeds from a species I've never heard of on ebay, or a species that is technically "rare", I wouldn't buy it to boycott the collection of those. Maybe even report the item to eBay as a rare species being illegally collected and sold.
If you guys are really concerned about some species becoming extinct, you could always start some conservation groups to boycott the sale and prevent the collection of the uncommon species.
Just my thoughts and opinions.