Unfortunately if it is an Ethereal the Tau likely have Gue'vesa scattered throughout the ship along with veteran fire-warriors and a good number of the smaller battle suits, to ensure any strike against the Ethereal ends in at<em>best</em>mutually assured destruction and more likely have a good percentage of the pilots converted to Gue'vesa with a few ships hidden somewhere in system the entire group can retreat to.<br/><br/>More likely they have done everything above<em>and</em>the Ethereal is a decoy.