I moved out of the Netherlands a couple of years ago, this makes me feel ashamed. The authorities handled this so poorly that it just had to explode into riots.<p>Two years ago similar problems where arising in France, called Apéro géant. The crowds intended to organize the biggest party at the Eiffel Tower, everyone feared problems.
Authorities sealed the surroundings, but let everyone pass through as long as they handed in their alcohol. Once arrived at the location there was not much of a party so nothing happened.<p>It's going to be interesting to see what happens to social media monitoring, also interested to see what happens with the damages and the people on tape (youtube, fb et all)