sharing: Remove auto-destroy notification

rfc/src/sharing.xml

@@ -174,7 +174,7 @@ for this principal that the user has access to, or null if none.</t></li>
 
 <section anchor="auto-deletion-of-notifications"><name>Auto-deletion of Notifications</name>
 <t>The server <bcp14>MAY</bcp14> limit the maximum number of notifications it will store for a user. When the limit is reached, any new notification will cause the previously oldest notification to be automatically deleted.</t>
-<t>The server <bcp14>MAY</bcp14> coalesce notifications if appropriate, or remove notifications that it deems are no longer relevant or after a certain period of time. The server <bcp14>SHOULD</bcp14> automatically destroy a notification about an object if the user subscribes to that object.</t>
+<t>The server <bcp14>MAY</bcp14> coalesce notifications if appropriate, or remove notifications that it deems are no longer relevant or after a certain period of time.</t>
 </section>
 
 <section anchor="object-properties"><name>Object Properties</name>