Picking lane during Champ Select Screen

During the Champion Select screen...After it shows all 5 players have joined the room. I can be either the 1st or 2nd to call a lane (ie: Top). Then another player tells me no - I called it before you did. How can that be? I think that is a way to bully to get the lane I called. It has happened several times very recently. Once a player said I joined late. After I selected a lane no one else called on my Champion Select Screen. Can you tell me what is causing that to happen? I even copied my screen showing I called the lane first and pasted it in the Champ Select Screen - yet they still tell me "I Called that lane before you did"...