It is a known fact that eZFind only returns main node location of a searched object.

This results in some constraints that would be avoided if eZFind became aware of multiple locations

Steps to reproduce

Create an object. Add a secondary location. Hide the primary location.
Search for it, as anonymous, in the front end. The object will be listed but you won't be able to open it, since the url points to the hidden location.

Create one folder and a role that grants users content/view privilege to that folder. Create an user (A) and associate it with this role alone. Create an object on some other location. Add this folder as a secondary location.
User A will be able to browse and view the object in the front end but if he searches for it no results will be displayed.