Remove user details to a seperate "offline" table

While talking about GDPR at ITNation EU, someone mentioned that e.g. historical tickets contained information that enabled individuals to be identified, and that this could be a security concern. My thought here is whether it would be possible to optionally reduce the identifying information to a simple ID, but be able to reference this elsewhere (e.g. and "offline" table. Might be impractical but thought I'd mention it.