thanks so much for this.
We implemented it, but there's still two problems.
This is working:
People who post on my blog are "contributors." They now cannot see emails / IP addresses in the comments (under "manage" or in the comments on the front end).
This is not working:
In the Manage-->Posts, you can click on the number of comments and see the full range of info. on the commenter.
The full information is available whether you were the post writer or not. (It so happens that I don't even want post contributors to see this.)
Authors of posts (regardless of status) receive an email notifying them of comments to their posts. Those also show the full IP/email info.
I do not think there is a built in check-box to disable that in WordPress, as I searched for one.