In the hope of putting out some anti-journo flames:
Mr Shoesmith said:
"The very fact that TCAS appeared to save the day suggests it's no laughing matter, since it's often not to be 100% relied upon."
I took him to mean that TCAS is not infallible, and that you should not rely on TCAS to avoid collisions. If you get an alert, something has already gone wrong.
I did NOT take him to be saying that pilots should not follow TCAS directions, if the thing goes off.
I can see the potential for ambiguity, but "not to be relied on" is not the same as "not to be obeyed."
Peace and love