I know I've seen that screenshot posted around for years now. SE should make an official statement somewhere since we have since seen GM screenshots that counteract the call from that GM.

Regardless, if you were active and they labeled the reason as "AFK" which is what it sounds like they did, then you were right to report them. I hope you included that statement. Sounds like they may have bitten themselves in the ass not realizing that the other person was with you and could provide that evidence.