upstart/sessions/gpg-agent.conf starts gpg-agent unconditionally

I have a Xenial system; gnupg-agent 2.1.11-6ubuntu2 is part of the install.

In /etc/X11/Xsession.d/90gpg-agent , gpg-agent is started if either ~/.gnupg/gpg.conf or ~/.gnupg/options contains a "use-agent" directive. This part is working fine, as far as I'm aware.

Now, the /usr/share/upstart/sessions/gpg-agent.conf file contains this comment:

    # /etc/X11/Xsession.d/90gpg-agent starts the agent without DBUS,
    # thus can't use pinentry-gnome3
    # but we know we have dbus now, restart gpg-agent

Okay, so when gpg-agent was started by Xsession, it had been started without DBUS, so then this re-starts it with DBUS awareness. I can understand that.

The problem is that this Upstart config starts gpg-agent regardless of whether it was previously running or not. So the Xsession script's careful logic to check for "use-agent" in the GnuPG user config files is for naught.

I don't use gpg-agent, and don't want it running in my X session. (I want ssh-agent, and nothing else.) The "use-agent" directive is exactly the kind of mechanism I'd want for controlling whether or not this daemon is started. The Upstart config file should not run roughshod over that.