Update docs to clarify backup location and relationship with other da…

…ta (#3309)

* Clarify backup location information in the docs
* Update wording a bit

Signed-off-by: Abigail McCarthy <mabigail@vmware.com>

site/content/docs/main/locations.md

@@ -7,7 +7,7 @@ layout: docs
 
 Velero has two custom resources, `BackupStorageLocation` and `VolumeSnapshotLocation`, that are used to configure where Velero backups and their associated persistent volume snapshots are stored.
 
-A `BackupStorageLocation` is defined as a bucket, a prefix within that bucket under which all Velero data is stored, and a set of additional provider-specific fields (AWS region, Azure storage account, etc.) The [API documentation][1] captures the configurable parameters for each in-tree provider.
+A `BackupStorageLocation` is defined as a bucket or a prefix within a bucket under which all Velero data is stored and a set of additional provider-specific fields (AWS region, Azure storage account, etc.). Velero assumes it has control over the location you provide so you should use a dedicated bucket or prefix. If you provide a prefix, then the rest of the bucket is safe to use for multiple purposes. The [API documentation][1] captures the configurable parameters for each in-tree provider.
 
 A `VolumeSnapshotLocation` is defined entirely by provider-specific fields (AWS region, Azure resource group, Portworx snapshot type, etc.) The [API documentation][2] captures the configurable parameters for each in-tree provider.