Techs can be unlocked out of order

[ec429]

If you have a tech A which is a prerequisite of B, and you queue both up, you can then re-order them on the R&D pane of the KCT GUI such that B unlocks first.
Since re-ordering is done by moving techs one slot at a time, bubble-sort style, a sufficient condition to prevent this would be to check that when swapping two techs, the first is not a direct prerequisite of the second; as long as the initial order is valid this will prevent any tech moving before any of its ancestors.
However, I don't know whether KCT has the necessary information available to check for this.