Make into a warning as suggested by @dstufft
diff --git a/docs/fernet.rst b/docs/fernet.rst
index 4e618f5..68184b3 100644
--- a/docs/fernet.rst
+++ b/docs/fernet.rst
@@ -39,10 +39,13 @@
:param bytes plaintext: The message you would like to encrypt.
:returns bytes: A secure message which cannot be read or altered
without the key. It is URL-safe base64-encoded. This is
- refered to as a "Fernet token". Note that this contains
- the current time when it was generated in *plaintext*,
- the time a message was created will therefore be
- visible to a possible attacker.
+ refered to as a "Fernet token".
+
+ .. warning::
+
+ The encrypted message contains the current time when it was
+ generated in *plaintext*, the time a message was created will
+ therefore be visible to a possible attacker.
.. method:: decrypt(token, ttl=None)