Clarify that spooling locations must not be shared

docs/src/main/sphinx/admin/properties-client-protocol.md

@@ -154,11 +154,14 @@ Examples:
 * `s3://my-spooling-bucket/my-segments/`
 
 :::{caution}
-When using the same object storage for spooling from multiple Trino clusters,
-you must use separate locations for each cluster. For example:
-
-* `s3://my-spooling-bucket/my-segments/cluster1`
-* `s3://my-spooling-bucket/my-segments/cluster2`
+The specified object storage location must not be used for spooling for another
+Trino cluster or any object storage catalog. When using the same object storage
+for multiple services, you must use separate locations for each one. For
+example:
+
+* `s3://my-spooling-bucket/my-segments/cluster1-spooling`
+* `s3://my-spooling-bucket/my-segments/cluster2-spooling`
+* `s3://my-spooling-bucket/my-segments/iceberg-catalog`
 :::
 
 ### `fs.segment.ttl`

docs/src/main/sphinx/client/client-protocol.md

@@ -59,6 +59,8 @@ on a Trino cluster:
   [](prop-protocol-spooling).
 * Choose a suitable object storage that is accessible to your Trino cluster and
   your clients.
+* Create a location in your object storage that is not shared with any object
+  storage catalog or spooling for any other Trino clusters.
 * Configure the object storage in `etc/spooling-manager.properties` using the
   [](prop-spooling-file-system).