Thanks for covering the plugin update, Sarah. I need to hire you to start writing my plugin release announcements on my blog. :)

On the capability registration feature, I do want to note that other plugins aren't required to register caps, just in case that wasn't clear. Members has and will almost always pick them up automatically. The registration aspect is just nice for end users who might need a translatable label/title for the cap. I plan to write more about this more in depth soon.