Ensure that the locking/opening process is carried out correctly to ensure the safety of the service personnel and that the sleeve is placed at the very bottom of the stroke before the brake maintenance work is performed. If you do this, you don't need to lock the sleeve anymore.
Allowing press operators to join the maintenance press allows them to alert maintenance or management personnel whenever problems arise. They operate the press every day, making it easier to hear or see signs of problems. Just like driving the same car every day, you can notice the abnormal sound in the first time, which is the same for the operator.