If she eats any grains at all, she's most likely not eating gluten free. The standard for gluten free is extremely, extremely sensitive, and cross contamination is almost certain.
You have to be eating things that are 100% certified elisa tested to be gluten free - so far as I am aware, only a few products meet this standard.
Are you suggesting that if I eat some grass fed beef that hasn't been elisa tested, there's a good chance I'm eating gluten? This seems patently ridiculous to me. The elisa test is also flawed - there are situations in which it can't detect hydrolized gluten.
In any case, quantity matters. Trace amounts of gluten due to cross contamination may not be enough to cause people significant problems. You don't have to be 100% gluten free to derive benefits from it.
You have to be eating things that are 100% certified elisa tested to be gluten free - so far as I am aware, only a few products meet this standard.