Just to add some more fuel to the discussion... I always assumed kT referred to "displacement", like it does with sea-faring vessels. In which case "1 kT" means it displaces 1 kT of water. At which point it has less to do with mass than with volume. (Although one could argue that density was the important factor, but that's just mass divided by volume, so that 1 kT still isn't really mass (or even weight, which is a measure of the effect of a gravitational field on mass)).
Have fun debating!!!
