As assistant patrol leader what should I do if a fellow scout is wearing the uniform wrong?

This Applies to even the Armed forces. I served 8 years in the Marine Corps. and one thing they taught us was: "Corrections can be made at any level." Meaning a private can walk up to a general and tell him that he is using his uniform wrong. And need to fix it immediately. But be respectful about it. Tell him according to policy the uniform needs to be worn properly and in a professional manner. Some people might laugh and brush it off, others might tell you to go away. You need to squash small discrepancies so that it will discourage the bigger issues. No room to tarnish or sacrifice your integrity. Make no exceptions, friend or not.