Over-reaction lovebunny... "Investigation"? As in phone SS or police bang down their door or what?
There is certainly a consensus against blatantly sexualised stuff for pre-teen children on this site (cf. "Let Girls Be Girls") but some parents think differently and would find it funny. I know that 10 year old girls would find it a right laugh to be wearing something with "I heart sex" on it, and as most of them have got flat chests and still think sex is "creepy" and "disgusting" it would hardly mean anything.
If someone was raping their 9-11y/o daughter or wanted somebody else to have sex with them, do you think they'd let them wear this anyway? Paedophiles are sly and deceptive, apart from the ones with learning difficulties/ (other) mental health problems who luckily tend to get caught faster. They wouldn't attract attention to a child by dressing them in this.