good question

I have CPR licence. Good Samaritan Law pretect providers to help injured people. If you are the professional required to perform CPR such as firefight, law enforce officers, lifegards you have to perform CPR during your work, Off duty, you can choose no. 

So as a professional during the work, you are responsable to follow the protocol, off duty if you choose perform CPR, like others, pretect by Good Samaritan Law.

Another thing, you may know privacy about the person you CPR, then You MUST not share this info with other people.