Turning, running and screaming is a guarantee to get run down and bitten/mauled. Standing in place, no eye contact and calm.....now, try and teach this to kids..much less adults..when a large dog is charging at you....good luck... It would take a cool operator to stand in there calmly, most wouldn't be able to ...even if it is the proper method to practice.
I'd evaluate the situation and be realistic as to the capabilities and capacities of the kids and go forth with your plan. My guess is, it would be best to have the kids simply leave the area as soon as they see this particular dog rather than a wait and see mentality. Having options is the name of the game....never give up your options willingly....unless there is a better one.