Is it time to start calling out bad cyclists?

To the older lady with a beret on a red "pasley" pootling down Holloway road: riding down the left-hand side of lorries and trucks at choke points is going to get you smooshed! Please don't do that in front of me when I'm trying to enjoy my sunny Friday cycle in to work! Riding and wincing all the way down Holloway road probably made me look a bit special..

Surely you should say something?