I haven't thought it though but it would be kool to have a program that automatically invites someone who invites you.

I know we can adjust privacy settings that will block invites. Lately I've been manually inviting the person who invited me and they join much of the time.
When people are inviting everyone on their lists they probably get some pop-ups about someone not accepting for some reasons, if my invite pop-up shows up in the while that is going on they click accept by accident I think.