Final answer:
The statement is false; both existing and new data will be replicated when an existing non-clustered indexer is added to the cluster to ensure data consistency across all nodes.
Step-by-step explanation:
False. When you convert an existing non-clustered indexer to become a part of the cluster, not just the new data but the existing data should also be replicated across the cluster. This process ensures that all nodes in the cluster have the same data, enabling them to serve queries and balance the load effectively. In a clustered environment, the redundancy of data helps in achieving high availability and fault tolerance.