I believe it to be an application-level setting that applies to that Word session.
Haven't tested it.

I know of no way to set the document for this setting without a macro. Once the document is on a different machine, it will have no effect until the setting is run on that machine.

If the macro is in the template and a document based on the template is opened or created, it will be run so long as the document remains attached to the template.

It should be possible to first capture that option state in a document variable when the macro is run and return to that state in a macro that responds to the Document_Close event. I have not attempted this because, frankly, I want the option set this way on all of the machines in my office. I have a number of macrobutton field using checkbox autotext in my non-protected legacy forms.

Single-Click Checkboxes in non-protected forms