Comment # 22 on bug 752842 from Jiri Bohac

Privacy extensions should default to OFF.

Quoting RFC 4941, section 3.6.  Deployment Considerations:

   The use of temporary addresses may cause unexpected difficulties with
   some applications.  As described below, some servers refuse to accept
   communications from clients for which they cannot map the IP address
   into a DNS name.  In addition, some applications may not behave
   robustly if temporary addresses are used and an address expires
   before the application has terminated, or if it opens multiple
   sessions, but expects them to all use the same addresses.
   Consequently, the use of temporary addresses SHOULD be disabled by
   default in order to minimize potential disruptions.  Individual
   applications, which have specific knowledge about the normal duration
   of connections, MAY override this as appropriate.