'Certified Gluten-Free' doesn't mean a wheat-free facility. Nope. Every label, every time. And call manufacturers often. My husband just bought cereal that was certified gluten-free but made in a facility with wheat, soy, dairy, tree nuts, and sesame. It's for him, but the label caught my eye. I could see some wheat-free families getting caught by this if they think everything with the certification is safe.
http://www.gfco.org/get-certified/faqs/We just stopped using Natura soy milk because my last call and email (this summer) resulted in news that they would be adding almond to their facility soon, with shared lines. Whilst I was away last week my husband called me to say one of
his containers of soy milk tasted distinctly of almonds. Phew, dodged that bullet... but the fact manufacturers don't have to disclose that manufacturing change on labels is disturbing. (Same thing happened with the brand of popcorn we used to buy for years and years too.)