Locking all tcodes and then unlocking only some reporting. Yes, that would probably work to create a reporting only daily copy of a SAP system. Nice idea actually!
Whether that fits the shoe of a production system which is to be frozen against changes might be challenged by the tcodes which are multi activity capable and not reporting.
Thanks for the background and sharing the idea - will keep it in my sleave for a rainy day :-)
Cheers,
Julius