I consolidated all the warnings and caveats into a single introductory section for adding beta testers, and took them (mostly) out of the two sections on how to add beta testers. 

I'm kind of feeling like we're over-documenting this feature though. The label is pretty self explanatory, there's popup help, it's described (now) in the introductory section, so to have three more sentences describing it here, and why you might want to do it, seems like a lot to me... That said, if you still feel it needs more explanation, let's look at all of those point of communication and not just this one.