BuddyPress.org

Somewhat agree, is there a feature request for something like this?

Invite shouldn’t be possible without acknowledgment as those group members are then subject to posts, messages, etc. HOWEVER, admin should be able to invite any one to any group without being friends. The group functions isn’t exactly intuitive to people that aren’t savvy with the internet so being able to send members invites to appropriate groups to pull them along a little is a good idea.