Is it safe to enable this policy L

Is it safe to enable this policy on windows vista machines:
Domain member: Digitally encrypt or sign secure channel data (always)


After reading this :http://support.microsoft.com/kb/823659 ,you can see that
there is a warning that enabling this policy will case Microsoft Network
clients to receive one of the following error messages :

Logon failure: unknown username or bad password.
There is no user session key for the specified logon session.