Which scenario does not necessitate re-indexing existing data?

Re-indexing existing data is a process typically required when changes have been made to the structure or attributes of data that affect how that data is accessed or queried. In this context, importing data using TC XML utilities does not require re-indexing, as this process involves adding new data rather than altering existing data structures or attributes.

When data is imported using TC XML utilities, it is essentially being appended to the system without impacting the indexing of previously existing data. The indexing mechanism is primarily concerned with how data is organized for efficient retrieval, and importing data does not modify or require updates to the existing indexing structure.

In contrast, scenarios such as modifying existing data attributes, changing user permissions on data, or updating relationships between objects all potentially affect how data is accessed, retrieved, or related to other data. Such changes could require the system to re-index to ensure that data remains accessible in accordance with the new configurations.