Yeah, we were snickering a bit here in America after all the "Only in America" comments we got year after year from you guys. 
In the USA we have our moments of dickishness on Black Friday, but there is an unspoken etiquette we follow. Most of it is a fun sport to see what you can grab before everyone else, and most people are gracious about the game. Believe it or not I'd say 9/10 shoppers I've run into are pretty chill about the whole thing, provided you don't shove too hard. For the most part, it's not too different than shopping a few days before Christmas in a packed shopping mall.
If you compare the number of actual incidents to the number of stores we have it's actually quite small.
It did get pretty bad during the recession during 2007-2011 at Walmart because that was the only time people could afford anything for Christmas. But we have better measures in place now.
I think once you guys get better crowd control measures in place, you'll do fine.