That's incorrect. And I (and everyone else) would appreciate if you guys stop providing wrong information. All information about GCMS request can be found online at cic.gc.ca/english/department/atip/requests-personal.asp and it explicitly says it is recommended to provide consent form for anyone over 18 years old.
From my personal experience, the first time i applied and didn't provide the consent of my wife, my request was refused. So yes, it might fly in certain cases/officers, but do you really want to take a chance and waste a whole month waiting?