my experience is that the manufacturer is listing on label if the product was made in the same facility where they process wheat, tree nuts, soy +etc therefore contamination is more likely.
Nature's Path has a few products GF and they state that on the box. EnviroKids is moslty GF
my own rule of tumb is:
1. known ingredients (knowledge is key) = YES
2. see clearly GLUTEN FREE on the box = YES
3. product was made in the same facility where they process wheat, tree nuts, soy +etc = NO NO
4. if i am not sure = NO, i do not buy it.
there was a new law in US which came out Jan 2006 which required manufacturers to state clearly with the ingredients if the product contains any one of the allergen, like:
tree nuts, soy, peanuts, wheat, eggs, etc, etc...