diff --git a/pep-0278.txt b/pep-0278.txt
index e2cebc7a8..a359d5878 100644
--- a/pep-0278.txt
+++ b/pep-0278.txt
@@ -40,7 +40,9 @@ Specification
     In a Python with universal newline support open() the mode
     parameter can also be "t", meaning "open for input as a text file
     with universal newline interpretation".  Mode "t" cannot be
-    combined with other mode flags such as "+".
+    combined with other mode flags such as "+". Any line ending in the
+    input file will be seen as a '\n' in Python, so little other code has
+    to change to handle universal newlines.
     
     There is no special support for output to file with a different
     newline convention.
@@ -77,7 +79,8 @@ Rationale
     programs are expected to handle this by themselves or write files
     with platform-local convention otherwise.  The reason for this is
     that input is the difficult case, outputting different newlines to
-    a file is already easy enough in Python.
+    a file is already easy enough in Python. It would also slow down
+    all "normal" Python output, even if only a little.
     
     While universal newlines are automatically enabled for import they
     are not for opening, where you have to specifically say open(...,