Nut allergies, sure. But I’ve never heard of someone with celiac not being able to touch something with gluten in it. Someone here claims their child does, but that sounds surprisingly niche to be in a regular toy aisle. The sand just mentions about being gluten free.
I don’t know, I just don’t know why anyone would expect sand to have gluten in it in the first place, even a parent with a gluten-sensitive kid. It’s sand.