Board Thread:Support Requests - Community Management/@comment-25876622-20160810011210/@comment-452-20160810025812

Yes, the "Prevent logged-in users from editing from this IP address" setting is for when you're blocking an IP, and does nothing when blocking a username. When blocking an IP, unchecking that box displays "anonymous users only" in the block summary.

Whenever I deselect it when blocking a user, it is still checked when I review the block. This must be by design, because when you think about it, NOT preventing the user you are blocking from editing means no block at all.

I've never been able to work out why it's even present on the block screen when blocking a username.

I agree that it's confusing though.