Thanks for posting your question here in the Pega Product Support Community. I am currently researching an answer to your question. I'm not sure if you're aware but we have a Pega Academy Community that is available to answer course related questions. In the future I would like to invite you to post course related questions there.
Hope to see you there!
Maryrita Styer | Community Manager | Pegasystems Inc.
As it is an out-of-box rule from PEGA, it will not allow to save or check in which in turn makes the change reflect to other users using the same server on which the PRPC installed. Hence it allows private edit which causes the changes reflect to the current operator and save as which ask for a rule set to save it in.