Tetsing version...
[root@jsefler-betaqa-2 ~]# rpm -qa | grep  subscription-manager
subscription-manager-firstboot-0.93.15-1.git.12.5bcf723.el6.x86_64
subscription-manager-0.93.15-1.git.12.5bcf723.el6.x86_64
subscription-manager-gnome-0.93.15-1.git.12.5bcf723.el6.x86_64

rhsm-compliance-icon -f warning
rhsm-compliance-icon -f expired

both show a fuelgauge icon that is "full"
I expected the expired icon to be shown as "empty"  (am I wrong?)

Moreover, there is no icon on the window manager when running subscription-manager-gui.  in the past an icon was used here.

See attachment

Created attachment 476890 [details]
should the subscription-manager-gui icon also be a fuel gauge?

Looks like this may be an older version.  Can you try with 0.94.3?  I just verified that this shows up on a RHEL6 machine.

subscription-manager-gnome-0.96.1-1.git.4.6eda843.el6.x86_64

This shows to be working in the above build ^

An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHEA-2011-0611.html