I'll be honest - I got the skin from the promotion. That said, it is a really bad promotion. Riot could have potentially given away ~$30k worth of skins this weekend for the promotion. With each giveaway, 1000 people got a skin and then promptly stopped watching the stream (after the first Infernal of the weekend, the collective viewers across YouTube and Twitch went from ~6500 to ~5500).
This didn't do shit to grow the OPL's fan base. It just lost Riot $30k.
If you want to reward the viewers for watching OPL, don't put the promotion on the front page of the client because non-viewers will come, get the skin, and leave. If you want to reward the viewers for watching the OPL, announce it during the broadcast or put it on the front page of oce.lolesports.