They're not going to measure, just like NCA doesn't measure skirt length even though they have it in their rules. If your crop top stops at your bra and your skirt stops 3 inches below your belly button, you might get hit with a penalty. I'm sure it's just there as a guideline for when ordering. The NCA rules make more sense than this arbitrary 10" rule though.
Female Cheer Tops
• Standard shell, crop, or midriff top
• No “bra top” style or size tops – material must fall at least one inch below the bra line
• No extremely low cut necklines
• No excessively bare or backless style tops
• Must have solid material around the back
• No “tube tops”
• Must be secured by straps or material over at least one shoulder or around the neck
Female Cheer Skirts
• Must fully cover the hips
• Must completely cover briefs when feet are shoulder width apart AND, in the back, fall at least 1.5
inches below boy-short briefs or 2 inches below standard briefs
• No excessively short or tight skirts
• No ultra low rise waistbands (no lower than 2 inches below navel) when worn in conjunction with
a cropped or midriff baring top