Why must X open TCP by default?

[Chris H]

Hello,
 This is regarding 9-STABLE. All of the 9-STABLE boxes
that have Xorg installed, and running on them, insist on
opening TCP port 6000; as reported by sockstat(1)

Xorg       1295  1  tcp6   *:6000                *:*
Xorg       1295  3  tcp4   *:6000                *:*

I see that the (current(ish)) documentation indicates
that this option is off, by default, and can be enabled
by passing -listen_tcp to startx(1). This seems to hold
true, as all of my -CURRENT boxes do not show port 6000
as being open while X is running. So my question is;
how can I prevent X from opening tcp ports?
I attempted;
startx -nolisten tcp
startx -nolisten_tcp
but no joy. Is there an option available for xorg.conf(5)?
Maybe like
    DisableTCP true
or
    Option "DisableTCP" "true"
I couldn't find any hints in the man pages.
Anyway, any input greatly appreciated.

Thanks!

--Chris