Gizmodo just put out an article on the new OGL. Quoting their piece:
“According to attorneys consulted for this article, the new language may indicate that Wizards of the Coast is rendering any future use of the original OGL void, and asserting that if anyone wants to continue to use Open Game Content of any kind, they will need to abide by the terms of the updated OGL, which is a far more restrictive agreement than the original OGL.”
This would indicate that you can’t simply choose not to agree to the new OGL and ignore it. FYI. As with all things, if it matters to you, consult legal professionals.