The White March

On October 20 about 300,000 people (estimates range from 275,000 to 325,000, around 3% of Belgium's population)[1][2] marched through Brussels. Many Belgians who lived outside Brussels came to the city to take part in the march. This demonstration, called the "The White March", was the largest one Brussels had ever seen.

Everyone was carrying something white: a balloon, a cloak, etc.; some had painted their face white. White was meant symbolically, as the color of hope. This symbolism had grown after Queen Fabiola wore white at the funeral of her husband.

During the march, the fire brigade turned their hoses on the Federal Parliament buildings to symbolically cleanse it. With the demonstration, the Belgian public opinion wanted to indicate something had to change in Belgium and that the justice system and the police had to show more attention to children.

Aftermath After the demonstration so called "white groups" or "white committees" were created. Later on they formed a commemoration in Neufchâteau with about 6,500 people attending, including parents of missed and murdered children. The white committees often criticized Jean-Luc Dehaene, who was the Prime Minister at the time, because the guilty still had not been punished.

https://en.wikipedia.org/wiki/White_March

Few things to confirm: How can this be trusted - What's his experience in organizing protests - How was this date picked - Why can't people read the brochure now (I wouldn't advertise w/o knowing what's the message to be delivered).