True, but people may come from a variety of backgrounds where it's acceptable to do these things. I don't believe all people universally and instinctively know to stand on the right (left?) because people are walking by on the left (right?).

That's why I think it can be helpful to post signs, especially in a situation where the users may be from around the world. Granted, I'm thinking mainly of airports and other transport hubs here: places with a potentially international user base and places where the operator of the facility would indeed agree that there is a benefit to many people to walk instead of stand. I honestly don't care if my local mall posts the signs...the teenagers will ignore them and just stand there while they text anyway....

Can't hurt, right?