User blog comment:Thailog/Ep. 207 "Depths" discussion/@comment-76.220.44.198-20120608015655/@comment-5145408-20120608020346

if they (Artemis and Wally) haven't been on the team and (from their perspective) quit, not to return, they wouldn't have spent the time making up new costumes for themselves. so it makes sense for them to have the old costumes (at least that is my take on it).