Iowa health guidelines define an exposure as 15 consecutive minutes within a distance of six feet.

To avoid having to quarantine anyone should a student test positive, some Iowa schools are having students get up and move around every 14 minutes. https://iowastartingline.com/2020/09/09/musical-chairs-iowa-school-districts-new-way-to-skirt-covid-rules/

This is a painful example of Goodhart's law, which, as rephrased by Marilyn Strathern, states that "When a measure becomes a target, it ceases to be a good measure."

Avoiding 15 consecutive minutes of exposure became a target; clearly it's no longer a good measure of risk.

See also Campbell's law:"The more any quantitative social indicator is used for social decision-making, the more subject it will be to corruption pressures and the more apt it will be to distort and corrupt the social processes it is intended to monitor."

https://en.wikipedia.org/wiki/Campbell%27s_law

Be careful not to assign a “stupid yokels” narrative to the story. This is a deliberate end-run on the regulations, not scientific illiteracy.