Adding a disclaimer using a transport rule - is the Sent Items copy updated?

Hello,

In Exchange 2010, all sent messages are supposed to pass thru a H/T server.

If I configure a transport rule to add a disclaimer to all sent messages:

1. does that mean that the copy of the message in the user's Sent Items folder will contain the disclaimer?

2. is the behaviour the same in OWA?

3. is the behaviour the same in Exchange 2013?

For me, it seems logical to change the Sent Items copy in Outlook since it's a server-based message, which passes first via the Outbox anyway. How else can the user know what their correspondent got?

Thanks,

- Alan.