Every destructive script should refuse the first time
Dry run by default, back up before writing, read the value back, and exit non-zero when it did not work.
I write scripts that delete Outlook profiles and edit the registry on machines belonging to people who did not ask for it and will not be watching. Four rules have come out of that, and I now apply them to anything that changes state on a machine I cannot see.
Dry run is the default, not the flag
The safe mode should be what happens when you run the thing without thinking. If -DryRun is opt in, then the failure mode of a typo is a change; if -Force is opt in, the failure mode of a typo is a report.
Preview output has a second benefit I did not expect. It became the diagnostic tool. Running the repair in preview against a broken machine tells you exactly what is wrong with it, and quite often you learn enough from that to not need the repair.
Back up before the edit, not after the decision
The temptation is to back up the keys you are about to change. Do it before you evaluate whether to change them. The gap between deciding and acting is where the interesting bugs live, and a backup taken after the decision does not cover the case where the decision was wrong.
Read the value back
This is the rule I would keep if I had to drop the others. Write the value, then read it and compare. Silent write failures are real: permissions, policy, a key redirected somewhere you did not expect. If you do not verify, the script reports success and the machine is unchanged, and now the machine is marked as fixed and nobody will look at it again.
A tool that lies about what it did is worse than no tool, because it removes the problem from the queue without removing it from the estate.
Exit non-zero when it did not work
Scripts get wrapped. Someone will eventually run yours from a deployment tool, a scheduled task, or a loop over a machine list, and the only thing that layer can see is the exit code. A script that always exits zero turns a fleet wide failure into a fleet wide report of success.
Return 1 on failure. It costs one line and it is the difference between a bad afternoon and a bad quarter.
The underlying principle
Assume the person running this cannot see the machine, will not read the output, and will trust the exit code. Then write it so that is safe.
None of these rules make the script better at its job. They make it safe to be wrong, which on other people's machines is the more valuable property.