Please note I did not write the feature, nor have I been involved in the planning of it, so I am only going on how it works in the code (so anything I'm stating here could be mistaken).
I would argue that the marking workflow is pretty bulletproof, unless you have teachers who don't use it (at which point, there is nothing it can really do, as direct overriding of grades in the gradebook is out of its control). Maybe you could remove the capability 'moodle/grade:override' from teachers, if they cannot be trusted not to bypass the marking workflow?
However, if you feel the documentation can be improved then it is possible to edit it yourself - just visit the relevant page, click 'login', then create an account (if you don't already have one) and you should then be able to update the page.