Routine until it's not
At my last job all our changes were peer reviewed and any scripts that were to be run also had to have a peer review by someone with equivalent or greater scripting skill/experience. Production level changes went before a CAB except where they were declared 'routine' - routine being the change was successfully executed 10 separate occasions with no backout required, no incidents attributed to the change. Changes to the script would result in the counter being reset and the change could end up needing to be presented to CAB.
If the script hadn't changed since it was last run the peer review of the script wasn't mandatory but we did have to provide evidence that the script hadn't been changed for Production changes (timestamps, checksum or similar.)
Scripts had to be like for like across environments (Dev, Test, Prod (DR was classed as Production) unless there was a specific reason (different setup in Dev to Prod - client tried to save money with lower specs for some environments.)
At the time I got shoved out the door they were working on 'streamlining' processes and pushing the Agile line to speed things up. I had heard on the grapevine later on that my former offshore colleagues had tried to blame one of my old scripts for a major incident. What eventually transpired they had taken one of my scripts as a base, changed some of it's functionality for what they wanted and in the process removed the parts that backed up existing configurations/settings etc. They had presented it as being 'unchanged' so that they didn't have to go through CAB.