Please don't take offense...I know American style dancers can block the way as often as someone else can crash into them.

I always explain to my students about the 'lanes' on the dance floor. I usually explain that it's like a roller-skating rink, with stationary couples in the middle, then a slow progressive lane, then a fast lane on the outside. My older students understand right away, remember the roller-skating rinks. The younger ones look at me with dazed faces. I explain that was back when our four wheels weren't all in a line

For a really cute etiquette 'lesson', look on the Harvard Medical Area dance club page. http://www.hcs.harvard.edu/~hma-bdc/