I think it is sensible for some of the PPL four hours of instruments to be undertaken in IMC and I try and do this.
I dont think most people deliberately cheat, but probably get clues round the side of foggles.
Furthermore the visual sensation of seeing cloud in IMC helps disorientate, as does the increased turbulence which occurs.
In response to a previous post, if you are on your own it may only take one momentary lapse of concentraition to lose it into a unrecoverable unusual attitude!