In support of Pfeffer's view:
Video of someone who grows Carolina Reaper seeds for Puckerbutt. Puckerbutt provided him with Carolina Reaper seeds, he grows Carolina Reaper for Puckerbutt ONLY. All the peppers he grows are sold back to Puckerbutt. Notice how they are grown. Not in a green house. Not isolated in any way. In fact, non-reaper plants growing along side reapers, market with flags, not removed because the pollin has already spread by the time the pods have formed.
So, when you purchase Carolina Reaper seeds from the original cultivator, from the company that came up with the thing, what you are buying is open pollinated seeds.
That said, here is the the other side of the story. First year homesteading, I grew cantaloupe next to cucumbers and produced cucaloupe. On the outside they looked like cantaloupe. On the inside they looked like cucumbers. But let me tell you, despite the appeal of a sandwich size cucumber slice, they were horrible, bitter, and yuck. It is not just the seeds that cross polination can screw up, it is the fruit itself.
This is the second edition of a book that I have as a first edition. It was my introduction to seed saving, very easy ideas, isolation without entire green houses. Simple ideas like bagging flowers.
http://www.amazon.com/Seed-Growing-Techniques-Vegetable-Gardeners/dp/1882424581/ref=sr_1_1?ie=UTF8&qid=1419715034&sr=8-1&keywords=seed+saving
Thing is, there are two type of growers. Some folk buy seeds, grow, and then repeat the next season. Nothing wrong with that. Then there are seed savers. Business or not, these are the folk trying to improve the line as they go. Saving only the best, trying to prevent cross polination, and harvesting seeds from the best examples of the fruit. That's what has kept many of the heirloom varieties alive and well.
With seed savers and traders, it is a loved hobbey egged on by the idea of being self sufficient, not needing Walmart. But it is also about improving the line year after year. Your seeds become yours, your special dna. Its not the same as creating a new cultivar, but almost as rewarding if that is your thing. You look at your garden and say, ye baby I did that.
Example: Stars and Moons watermelon. Mine are the frigging brightest because when I first started growing them, the markings on them was what made my baby girl go ooohhh and ahhhh, so year after year I saved the seeds from the melons with the brightest markings.