Jim, OpenCandy is the means by which developers are able to offer an add-on, OC isn't an add-on itself.
In the same way as an add-on toolbar would have it's code integrated into an installer, OC code exist's in the installer - the matter of when and how we ban it comes if the user doesn't have the choice of whether to decline the actual installation of the add-on or not. If no opt-out existed, it would be banned. If the add-on was considered dangerous, it would be banned and in the case of OpenCandy, the first recommendation they make which is proven to be dangerous would result in their entire network being banned by us.
As for no mention on developers websites, well, they basically won't do this, most don't do it with any other addition to their installers so the inclusion of OC probably won't be any different - in an ideal world they would all be transparent but alas you and I both know it's not about to happen and if I took it upon myself to start removing everything I had moral doubts about we'd probably be left with a handful of downloads!.
Instead, I've started making a note of those downloads which contain OpenCandy and any other additions so we can draw people's attentions to it and ultimately the end-user has the final decision on whether they want to install the software or not - I'm just including a simple note in the description at the moment but after the upgrade I'll figure something a little more prominent