Out-of-state visitors are not granted an exception to the Gun Free School Zone statute when visiting another state, even with a validly recognized out-of-state permit.
That is a disputed interpretation. I do not know of any court cases testing it.
The first premise, that the exception only applies to residents of the particular state, is mistaken, as many states offer non-resident permits. The federal law does not specify the person licensed has to be a resident of the state, as far as I can determine.
As to whether "licensed by the state" applies to reciprocity, where the state recognizes licenses granted by other states, there is some ambiguity.
This scholarly article from 2017 explores the issues involved.
D. Conclusion The ATF's proffered interpretation of the term "licensed ... by the State" in the Gun-Free School Zones Act relies on an assumption that the term "licensed by," when followed by "the state" or reference to some other governmental unit, requires some licensee-specific affirmative act of the licensing state (or other governmental unit). However, the use of the term"licensed by the state," and correlative terms, are not so restricted.
It will probably take court cases to sort this out. I would be very interested to know of prosecutions which have occurred, of a person with a permit recognized by the state in which the prosecution happened.
Granted and agreed, but does not address the main point regarding why a Constitutional Carry state would need to recognize an out-of-state permit, so this exception was omitted for brevity.
As to whether "licensed by the state" applies to reciprocity, where the state recognizes licenses granted by other states, there is some ambiguity.
This scholarly article from 2017 explores the issues involved.
This does address why a Constitutional Carry state that permits non-residents to Constitutionally carry would want and/or need to recognize an out-of-state-permit.
Not being a lawyer, I was not familiar with that 2017 paper, and it was an interesting read. However, as it is a relatively novel premise and one not tested in the courts, I would hesitate to hang my hat on recognizing out-of-state permits to constitute being "licensed by that State" for Federal Statute purposes.
All other interpretations I have read assume that an actual document issued by the State is necessary to constitute "licensed by that State" for Gun Free School Zone (GFSZ) purposes. I would strongly recommend that the ATF's interpretation (as stated in that paper) be taken as prevailing law unless and until a court rules otherwise.
And since it is an untested premise, I don't think that it should be included in an article regarding Constitutional Carry, lest it give the reader an incorrect impression regarding the current state of case law.
Absent the GFSZ question, and the state reciprocity statutes I mentions previously, are there any other reasons why a Constitutional Carry state that permits non-residents to Constitutionally carry would want or need to recognize another state's permit?