In cross-tracker search widget, when writing a query with conditions on "always-there fields" such as @id, @last_update_date, @last_update_by, @submitted_on and @submitted_by, we ran a check on each tracker to see if they had the corresponding field. In a way it breaks the fact that the field is 'always there'.

Since those fields rely on data that is always stored (regardless of the presence of the field, the date and creator of an artifact is stored in the database), the field is not needed.

When the field is present, its permissions will apply and possibly restrict the artifacts matched by the query. When the field is absent, the data will be considered as safe to access, and the condition will apply. This means more artifacts can be matched by queries with conditions containing the "always-there fields" above.