(1) School band director In the US, public school band directors are generally either music education majors or education majors with a minor in music.Thus they fulfill the university's general requirements in math, English, social sciences and sciences (biology, chemistry, etc.) and they have taken music education and general education course that allows them to graduate.
The clear plastic tri-folds do not seem to cushion the eggs as well nor insulate as much as the foam. Pulp cartons are possibly more environmentally friendly being made of paper and all, but they cannot be cleaned. Once they get dirty there is nothing to be done but toss them.
In other words the ECT rated carton will use less corrugated material. For example compare a 275# single wall to an equivalent 44 ECT single wall corrugated board. On average, the 275# Burst Test rated single wall carton will weigh 175 pounds per 1000 square feet of material used.