I just went up against an OCE challenger player as an Unranked player.
Like I get that the OCE is a much smaller server. But I feel like Matchmaking could be a LITTLE better than that.
Not only were all the players on my team bronze and below, all of the enemy team save 1 were above gold 1.
So it's not like 1 person queued up on each team with a high rank, the match making system just decided that a challenger player belonged in that game.
Fun times Riot.