I think the most irritating part is the crowd that gathers just at the end of the plastic partition guarding the exit from the scanner. Usually one person starts to gather their things here and no one else can get theirs and also they have nowhere else to stand. The engineering solution would be to keep a steep slope the whole way to the end of the rollers so a tray won't stay still. People will want to lift theirs off to the side table to gather their collection of gold jewellery, or will be forced along creating space for the organised....