"What we want to know is, since when was it against the rules to have an American flag on a car, in a car, in your hands in a school?" student William Cassity said to 7News.
Two state lawmakers weighed in from their shared office at the Capitol on Friday with e-mails criticizing Stumpf's flag rule.
"Be prepared for legislative action and legal action against you to follow," wrote Republican Sen. Steve Johnson of Fort Collins.
His office mate, Sen. Tom Wiens, R-Castle Rock, said in an interview that Stumpf should have found some other way to ease the tensions in his school. "Clearly, there are ways ... to manage any sort of conflict that students might have that don't diminish the respect that we should have for the flag," Wiens said.
The ban includes T-shirts and other clothing that have replicas of the flags. At least for now, it also includes Mexican or American flags flown from the antennas of cars parked on school property.