That's in violation with the fundamental principles that underly Spring Data REST. If you have a repository for Address, you indicate that it is a separate aggregate. I.e. accessing the item resource for your Person would return two aggregates without making this obvious. This is problematic as then an update to that very same resource would have to change two different aggregates at the same time, which requires a transaction, a concept that not all backing stores that Spring Data REST can run on supports.
There already is a concept of excerpt projections that allow you to pull parts of the representation of a related resource into the _embedded clause of the representation of a resource.
Checking the reference docs, I realized that the section on (excerpt) projections deserves a bit of a polish up so that it's easier to understand the purpose of that functionality. I filed DATAREST-1377 for that