OK, what I vaguely remembered from Charles post was the part in red
'Most prosecutors will treat a "does not apply" provision like they would an "exception," but there is case law that holds the only exceptions are those expressly stated to be "exceptions."
So, legally, it appears that it would be a defense to prosecution, not an exception. I, however, would still use the argument that a hospital defined in 46.035 and owned by the government should not be able to post a 30.6/30.07 sign. Until case law shows up, we don't know 100% how they would rule.
