Removing the ability to ban a teammates "pre-pick"
Earlier today, and many times before, I have played with people who are either not aware that they are banning a teammates potential pick, or they troll and ban it on purpose. I see no reason why this should even be a possibility. To me it only makes sense that you can pre-pick and show what you are thinking, thus figuring out a good comp, and also letting your teammates know not to ban the champ you want.
Please share your thoughts on the matter.
EDIT1: I am going to include JesseBear's comment here. This expressed some of the points that I had trouble putting words to.
The problem is that more often than not, allies actually avoid banning your preferred champion and make meaningful decisions about team composition based on pick intent. It is only on rare occasions that a teammate will ban your champion, whether deliberately or inadvertently. If you are so afraid of being trolled that you refrain from displaying your pick intent, then you are also forfeiting the benefits that it could potentially give both you and your team. If you do display your intent, then you are taking the risk of revealing your preference to trolls. This really isn't a decision that should be forced. In my personal opinion, it would be better to just eliminate that choice by preventing people from banning pick intents, as Nickolai proposed. In such scenarios as Archangel Avacyn referenced, I believe that before banning your teammate's intended champion, you should reason with them first and get their permission. If they refuse to consent, then you have no business limiting their options. If they agree, then they can simply change their pick intent, allowing you to ban that particular champion.