I'm not a usage expert, but I don't think that's at all possible! A script isn't run by 'a user', it's run by your active InDesign. Any user privileges are surely derived from that. If you need other rights when running the script, you'll have to run ID with those other rigths.
Right, but doesn't the active InDesign inherit its rights from the User?
In any case, we'd like to be able to programmatically have diff rights for the script than the 'user' or 'InDesign'.