Cheating or "exploiting the grey area" will always be tried to gain an advantage and in this day and age of software I would think that's the way it now happens as anyone who designs it must know how to "fool it".
Blatant clever engineering like the 2005 BAR F1 secondary fuel tank when drained made the car 5.4 kg underweight or the 1995 WRC Toyota Celica with the brilliantly engineered turbo restrictor are "probably" a thing of the past