[ixm7]

I just got blocked for 1 hour due to multiple attempts to invite a friend to tournaments that were blocked for us. To avoid such false positives please consider:

1. Don't count invitations unless the other party actually saw the invitation. In other words, a blocked invitation is not an invitation.

2. If both parties to the invitation are marked as mutual friends, never treat invitations as spam.

Also, I understand why you don't want to test permissions on all tournaments as you list them (performance issues).
But how about testing permissions upon double-clicking on a tournament (and disabling the Invite button if an invitation would be blocked). That way, you would avoid "doomed" invitations.