The -noxmlns option reduces the amount of code and the size of generated data structures by removing most support for XML namespaces. Using -noxmlns changes the code in two ways:

Without fields for namespace declaration data, you can't provide namespace prefixes & URIs to be encoded with a given value. When a qualified name is encoded, XBinder will declare the namespace using a generated prefix or else a prefix it took from the schema document. If this is unacceptable to you, then do not use -noxmlns.

If the decoder ignores namespaces, that means it will accept invalid XML documents, namely those that use the correct local name but the wrong namespace for an element or an attribute. If this is unacceptable to you, then do not use -noxmlns.

Do not use -noxmlns if your schema uses namespaces and type extensions. The decoder would not be able to correctly determine an element's actual type from its xsi:type attribute in the XML document.

When the decoder ignores namespaces, it cannot distinguish between items that have the same local name but different namespaces. This is not a problem if your schema does not use namespaces or if your schema does use namespaces but either does not declare duplicate local names or else does not allow for XML documents in which, in a given context, multiple items of the same local name (in different namespaces) may appear. If your schema allows for such competing items, then you cannot successfully use -noxmlns.

Note: the compiler will not tell you if you are using the -noxmlnsoption when you should not.