Let me just preface this by saying my mmr is normal, nothing too high or low, 19 lp gains, 18 lp losses which is fairly standard for a diamond 5 player.
I queued up for a game, and got a 4 man premade, who proceeded to force me into ADC despite top/mid being my main. I knew this because of their club tags. I figured they'd be Plat 1 or something because in Diamond I can only duo with one friend at the most. During the game, I searched them up. They're all low plat or high gold. Enemy team is all mid to high plat. Objectively, I cannot see in any sense how this could be construed fair as to match a gold 1 player with a d5 player. I hope next season's ranked changes fix this. Seriously Riot, there needs to be a change.
Picture proof : http://imgur.com/a/kqBNC
EDIT : As you can see, none of them appear to be smurfs either, so it's not a case of they have really high mmr.