You will get a disclaimer like that from almost any company you ask. Even the manufacturers who put gluten-free on their packaging often do not have such verification for every single ingredient they use. The disclaimer is for legal liability purposes.
You may choose not to use such products, but by making that choice you will be excluding the vast majority of products available to us which are, in fact, safe to use.
I disagree. I've spoken to many companies about this kind of thing. Most know if their ingredients contain gluten or not. If they are not certifying their product, it is most probably because they know there is a gluten source.