Honestly this is the way I feel about "autolocking". First off blind pick is literally do whatever you want mode, don't get mad over it there. But in actual drafts I frequently see people fighting over roles or champions, the way I handle it is if two people want to top and neither wants to mid I tend to report the one who went mid as it means they actually tried to keep the game going. And if I'm on jungle for example I will NOT take the empty lane because the other players are being <word I can't say here>.
I recently had a game in blind where no one wanted to top, so our support decided to take it upon themselves to ditch the ad carry and then we not only had one lane down/behind but TWO. You're gonna get these people, the best action is to ignore them and just practice during the match. Unless you take control of their champions there's literally NOTHING you can do, and all worrying about a loss that is no ones fault but the players being toxic will impact your games negatively.
Further examples, I had TWO games in a row on Twisted Treeline with an afk last night, when I noticed the AP carries in those games were gone I took Lux, went back to spawn, got some ap items, blew up the enemy teams that thought they had the games in the bag because it was "2v3". Well it went about as well for them as hearing the words "enemy triple kill" every time the respawned would. Had I gave into the afks/people not wanting to play properly I would have lost.
And honestly, calling someone an autolocker or worse because they can only play one champion and/or role, is not going to help them play better. In fact ANY time my team starts to flame me I become less inclined to help them with plays and just make my own off on the side lane of the map. If you think someone is doing something wrong keep it to yourself (don't flame), try your best to win, and report them after.