Since safety is such a high priority in the construction industry and heavy fines can be placed on the employer if a worker is injured, you want to avoid responding as if it is not a problem for an employee not to wear their hard hat. If you avoid calling out a minor infraction, the interviewer might question your leadership and conflict resolution skills.

"If I saw a crew member not wearing a hard hat, I would ask them why they aren't wearing it. If it were because it did not fit right, I would find one that fits. If they were not wearing it because they did not feel it was necessary, I would remind them that the law requires employees to wear them, and the company could be fined, and the employee could be injured."