I've been told...

[polywog]

You can definitely create false reactions at the CQ's, but you cannot supress true reactions at the RQ's.  If both show huge reactions, the RQ's win and your countermeasures did not work !

[George W. Maschke]

Who told you this?

If reactions to relevant questions and "control" questions are both "huge" but nonetheless comparable in size, then according to DoDPI scoring criteria, the charts would be scored as inconclusive, not deceptive.

Actually, it is possible to suppress reactions to relevant questions on at least two of the three polygraph channels. Respiratory reactions are easily suppressed because respiration is under partial voluntary control. In addition (although AntiPolygraph.org does not recommend it), reactions on the electrodermal channel can be suppressed for all question types through the use of an anticholinergic drug such as scopolamine,  found in some anti-motion sickness preparations.