We did something similar with 'prod' code reviews. We started including a couple of the more junior folks in a pre-release review that was mandated. Intent was to say fine, id tech debt, or pull the andon cord if something was missed that would impact prod. What came out of it were their questions - which almost always was translated into an ask for documentation for that bit of code. The secondary bonus was they learned the questions that would be asked of the people who were merging.