[ntaso]

tl;dr: Forward arm and forward leg are on opposite sides, but many old pictures show them on the same side.

"Nobody" is a strong word though. I guess most artists nowadays get it right. At least people in animations/computer games.

Correct pose: http://www.angryanimator.com/tut/pic/002_walkcycle/wlk08.gif

[ericcholis]

I agree, modern artists seem to study the proper form. Take The Flash for example, a Google Image search shows that even the Golden Age (1930s) artists got it right