Why do we have to lock in champion or otherwise we will be kicked?

A little complain of mine about new champion select. In old champ select, you didn't have to click "lock in" to choose a champion, you only needed to click on him. But right now, it's not a case, if you don't click the magical "lock in" button, you are automatically kicked from champ select when your time for picking is over. Why was that changed? What if somebody, last second, thinks that other champ would do better in match? He's kicked, because he didn't click one additional button. So many times I saw somebody kicked out, because that person probably didn't even know such a change was implemented.