Well, then the droid does belong to you.
Luke: the droid says he belongs to you
Obi Wan, who knows full well that is anakin’s fucking nightmare robot: i don’t recall
Obi Wan didn’t realize he got custody of R2D2 in the divorce
Obi-Warn, knowing full well that R2 will do whatever the hell he feels like: I’m not taking any responsibility for him.