REST / OSLC How to determine if a user has been active in RRC?

CLM 4.0.7

We drive user authentication from LDAP and map an Active Directory group to the repository group JazzUsers.  Many people are added to that AD group but never use the tools, and when they leave, if we knew they had never been active, we could safely archive them without needing to first search for objects/artefacts they own and housekeep them.

For RTC, the query https://server:port/ccm/service/com.ibm.team.apt.internal.service.rest.IResourcePlanningRestService/workEnvironment?contributorId=_wHt2YKvUEeOUQv_f0tRWjg  will return an empty </workAssignment> element if the user hasn't been active or licenced (not sure which) and this seems a good enough check.

For RRC, I haven't been able to find any kind of equivalent query.  Can anybody comment whether this is actually possible, and if so what the query would look like?