Why the escalator etiquette of 'stand right, walk left' is wrong - Macleans.ca
Whether riding escalators or merging traffic, people feel they know what's fair, and it's messing with the work of transit operators and traffic planners
People have accidents+issue when walking, trouble getting on and off. But biggest issue is lots of weight on one side makes it more likely to break down. Cheddar did a good short video on this
also worth reading.