DOCS-15423 corner case dropdatabase (#45)

* DOCS-15423 corner case dropdatabase

* Review feedback

Author: Dave Cuthbert

source/reference/mongosync.txt

@@ -150,6 +150,25 @@ may differ between source and destination.
 Transactions may appear non-atomically on the destination cluster.
 Retryable writes may not be retryable on the destination cluster. 
 
+Profiling
+~~~~~~~~~
+
+If profiling is enabled on a source database, MongoDB creates a special
+collection named ``<db>.system.profile``. After synchronization is
+complete, {+c2c-product-name+} will not drop the
+``<db>.system.profile`` collection from the destination even if the
+source database is dropped at a later time. The ``<db>.system.profile``
+collection will not change the accuracy of user data on the
+destination.
+
+Views
+~~~~~
+
+If a database with views is dropped on the source, the destination may
+show an empty ``system.views`` collection in that database. The empty
+``system.views`` collection will not change the accuracy of user
+data on the destination.
+
 Examples
 --------