What if the sticker is for the driver? Like he/she knows that a small part of the view along that side is obscured so takes longer to look and make sure it's clear before turning or changing lane?
Van drivers don't have any special training if they passed there test long enough ago. I passed my test in a Vauxhall Nova 1.1 and can drive a long wheelbase transit as a result.
What if the sticker is for the driver? Like he/she knows that a small part of the view along that side is obscured so takes longer to look and make sure it's clear before turning or changing lane?