We have been using mod-user-import to begin importing user records.

It appears that if you are using mod-user-import, and you set one user record to have a value for externalSystemId, it expects all of your users to have a value for externalSystemId.

This is problematic since it's not a required field on the user record and may not always be present in a bulk load of users, depending on the institutional approach to loading those records.

It's clear that mod-user-import needs to have a match point, but I'm submitting this to flag this behavior in consideration of whether you should be able to use other match points in the system (like barcode or username.)