Add that pv's access modes are not constraints on the volume.

Author: s-kawamura-w664

content/en/docs/concepts/storage/persistent-volumes.md

@@ -477,6 +477,15 @@ In the CLI, the access modes are abbreviated to:
 * RWX - ReadWriteMany
 * RWOP - ReadWriteOncePod
 
+{{< note >}}
+Kubernetes uses volume access modes to match PersistentVolumeClaims and PersistentVolumes.
+In some cases, the volume access modes also constrain where the PersistentVolume can be mounted.
+Volume access modes do **not** enforce write protection once the storage has been mounted.
+Even if the access modes are specified as ReadWriteOnce, ReadOnlyMany, or ReadWriteMany, they don't set any constraints on the volume.
+For example, even if a PersistentVolume is created as ReadOnlyMany, it is no guarantee that it will be read-only.
+If the access modes are specified as ReadWriteOncePod, the volume is constrained and can be mounted on only a single Pod.
+{{< /note >}}
+
 > __Important!__ A volume can only be mounted using one access mode at a time, even if it supports many.  For example, a GCEPersistentDisk can be mounted as ReadWriteOnce by a single node or ReadOnlyMany by many nodes, but not at the same time.