We are taking a field trip this week, and it's totally outside. No gift shop, no indoor restrooms, only the port-o-pottys. What would happen if I pump at 7 and then not again until 2:30? Would that be horrible and affect my supply? I normally pump at 7 and 12 for 15 min each time when at work, but I have no idea how to do it on the trip. It's not a great idea to leave my 23 5th graders with another teacher either.