Zimme, the tunnel though not necessarily full blackout should be conservatively modeled. The reason: In real life high Gs=stress and pain for the pilot. A lot of cases you hear of one guy out-turning the other amount to him being less hesitant to go ahead and put that stress himself. AH has got to simulate the fact that pulling G is NOT carefree experience in some way.
Oh, and if anything the redout for negative Gs needs to be made MORE punishing, completely ridiculous "porpoise" defense are way too common.