Chalk Stockings?

While watching In the Street last night, I noticed kids filling stockings with flour or chalk. They would then hit certain other kids with the filled stocking and leave a mark. One girl in particular seemed to liked being marked such.

Is this some form of Halloween ritual? (I ask because of the costumes.) Is it a lost 'trick'? Or is it another tradition imported with immigrants?

The only analogous festival I'm familiar with is Holi (aka Festival of Colours) in India.