diff --git a/hgext/rebase.py b/hgext/rebase.py
--- a/hgext/rebase.py
+++ b/hgext/rebase.py
@@ -29,9 +29,14 @@ def rebase(ui, repo, **opts):
 
     Rebase uses repeated merging to graft changesets from one part of
     history (the source) onto another (the destination). This can be
-    useful for linearizing local changes relative to a master
+    useful for linearizing *local* changes relative to a master
     development tree.
 
+    You should not rebase changesets that have already been shared
+    with others. Doing so will force everybody else to perform the
+    same rebase or they will end up with duplicated changesets after
+    pulling in your rebased changesets.
+
     If you don't specify a destination changeset (``-d/--dest``),
     rebase uses the tipmost head of the current named branch as the
     destination. (The destination changeset is not modified by
diff --git a/mercurial/minirst.py b/mercurial/minirst.py
--- a/mercurial/minirst.py
+++ b/mercurial/minirst.py
@@ -373,7 +373,7 @@ if __name__ == "__main__":
     text = open(sys.argv[1]).read()
     blocks = debug(findblocks, text)
     blocks = debug(findliteralblocks, blocks)
-    blocks = debug(prunecontainers, blocks, sys.argv[2:])
+    blocks, pruned = debug(prunecontainers, blocks, sys.argv[2:])
     blocks = debug(inlineliterals, blocks)
     blocks = debug(splitparagraphs, blocks)
     blocks = debug(updatefieldlists, blocks)
diff --git a/tests/test-rebase-parameters.out b/tests/test-rebase-parameters.out
--- a/tests/test-rebase-parameters.out
+++ b/tests/test-rebase-parameters.out
@@ -9,7 +9,12 @@ move changeset (and descendants) to a di
 
     Rebase uses repeated merging to graft changesets from one part of history
     (the source) onto another (the destination). This can be useful for
-    linearizing local changes relative to a master development tree.
+    linearizing *local* changes relative to a master development tree.
+
+    You should not rebase changesets that have already been shared with
+    others. Doing so will force everybody else to perform the same rebase or
+    they will end up with duplicated changesets after pulling in your rebased
+    changesets.
 
     If you don't specify a destination changeset ("-d/--dest"), rebase uses
     the tipmost head of the current named branch as the destination. (The
@@ -68,7 +73,12 @@ move changeset (and descendants) to a di
 
     Rebase uses repeated merging to graft changesets from one part of history
     (the source) onto another (the destination). This can be useful for
-    linearizing local changes relative to a master development tree.
+    linearizing *local* changes relative to a master development tree.
+
+    You should not rebase changesets that have already been shared with
+    others. Doing so will force everybody else to perform the same rebase or
+    they will end up with duplicated changesets after pulling in your rebased
+    changesets.
 
     If you don't specify a destination changeset ("-d/--dest"), rebase uses
     the tipmost head of the current named branch as the destination. (The
@@ -127,7 +137,12 @@ move changeset (and descendants) to a di
 
     Rebase uses repeated merging to graft changesets from one part of history
     (the source) onto another (the destination). This can be useful for
-    linearizing local changes relative to a master development tree.
+    linearizing *local* changes relative to a master development tree.
+
+    You should not rebase changesets that have already been shared with
+    others. Doing so will force everybody else to perform the same rebase or
+    they will end up with duplicated changesets after pulling in your rebased
+    changesets.
 
     If you don't specify a destination changeset ("-d/--dest"), rebase uses
     the tipmost head of the current named branch as the destination. (The
@@ -186,7 +201,12 @@ move changeset (and descendants) to a di
 
     Rebase uses repeated merging to graft changesets from one part of history
     (the source) onto another (the destination). This can be useful for
-    linearizing local changes relative to a master development tree.
+    linearizing *local* changes relative to a master development tree.
+
+    You should not rebase changesets that have already been shared with
+    others. Doing so will force everybody else to perform the same rebase or
+    they will end up with duplicated changesets after pulling in your rebased
+    changesets.
 
     If you don't specify a destination changeset ("-d/--dest"), rebase uses
     the tipmost head of the current named branch as the destination. (The