Black Friday warfare, are there rules or is it all fair in war and shopping?

If a family goes out with their kids, and they hand them a printout of the deals they are to hunt down and then turn them loose. When they meet at the designated check-in spot one of the boys is upset because he got one of the last two blanks and a woman seeing that she was going to be two person short of getting one, wrestles the item from the clutches of the boy (about 11yr). He tried hold on to the item but she was too strong. It technically wasn’t stealing because the boy or his parents had not purchased it, but extreme shopping such as Black Fridays are there any rules or every person for themselves?