as I can see on the replay he was afk 5-10 secs before saru was killed - so I don't see any reason not beliving him. Second I have played a lot of games with plat and I havn't seen him leave one game without a good reason, so I highly doubt he just left cus saru died. Third I have seen ppl like kugel and riz leave a lot games just cus they didn't like their team, or they lost a hero - and they did not get banned, because they are knowns and ppl plays a lot games with them. Plat is known aswell, mostly on asia tho, but some of us on euro knows him good aswell, so giving him another chance is more then fair imo - if he actually just left cus saru died.
From your view free I don't see you doing anything wrong, but from my view (I might have a bit more experience regarding bans) I disagree. And as I've understood from Anca I'm allowed to remove any bans other admins did If I have a reason, excluding him, so I'll remove this ban. If you still strongly disagree about what I've decided, I suggest that you make anca look at this topic and let him judge.