The coaches and Clerk of the Course should try for preventative officiating and warn kids before the race starts. Here are the NATIONAL rules ... so ALL XC in USA.
Jerseys: Tucked into the shorts in the Clerk's area and at the Starting Line.
Jerseys: Must hang below or be tucked into the waistband of the shorts when the competitor is standing erect.
Jerseys: Not be knotted or have a knot-like protrusion.
Shorts: Worn above the hips and waistbands are NOT to be rolled down for the entire race.
Bare midriff tops are not allowed.
Visible Undergarments: Unadorned (except logo) and of a single color. May have school identification per new rule.
Visible Undergarments: Do NOT have to be the same color.
Body Suits: Constitute a uniform. However, if worn under the uniform, are subject to undergarment rule (single color).
Socks are NOT part of the uniform.
Relay Teams: One person may chose to wear a visible compression short under the regular shorts and/or a visible undershirt without any other team member being required to do so.
Once two or more members do, they must be of identical color.
As long as team members wear the identical color and trim on their shorts, it doesn't matter if they differ in length and open/closed leg.
Jerseys should be the same basic color and style, the logo/manufacturer makes no difference.
Simple pins, barrettes, etc. as long as they don't stand out.
Earrings, rings, necklaces, and other items of visible jewelry are NOT allowed.
Yellow "Lance Armstrong" bracelets should not be worn (or visible).
Religious medal must be taped and worn under the uniform. A medical alert must be taped and may be visible.
No tape covered jewelry.
Navel ring not allowed only if becomes visible during a race … cannot inspect beforehand.
Items such as hats, bandanas, and sunglasses may be worn unless specifically prohibited by the Games Committee.
Watches are OK.