Is it possible to prevent users from adding new Members to Security Groups via the Security Admin? That is, if the Member doesn't already exist, the user is prevented or given an error when they try to add them to a Group? For the site I'm working on I'm decorating Member and managing it via ModelAdmin so I'd rather users couldn't also add Members via the Security Admin accidentally/on-purpose.
Thanks for getting back to me on this. The context for my query is in this post here [url]http://www.silverstripe.org/customising-the-cms/show/282214[/url] - I'd be very keen to hear your feedback on it?
I'll have a good look at MemberTableField and see what I can do. Your suggestion sounds like a pretty neat way to do it.