I think, for me, the best example is actually the ACE (Audio Capture Engine) plugin by Rogue Amoeba, which is used by a lot of 3rd party apps. It's quite popular, and it requires Reduced Security to install. I actually HATE that there is no (good) alternative to this software yet that can run within the bounds of the Full Security model. But I like that it's still possible to run this software. It feels like the warnings are adequate.