What situation are you envisaging that you suddenly get unexpected snap under or oversteer? If you go into a roundabout a bit to quickly you might get it – but even so you’re going relatively slowly so the consequences are actually not that serious. Compare that to driving at 60mph and someone pulling out on you and you have to slam on the anchors. I know where i’d prefer to have the best tyres, and which of those two scenario’s i’d rather protect against.
Under and oversteer are usually induced by hamfisted driving or external factors like diesel on the road, You can’t do anything about the second case, no rubber will help you there, and being a more careful/better driver is what is needed to counter the first case – not better tyres. However, one risk we all face every time we go out on the road is that we may need to perform an emergency stop. In that case you certainly want your best rubber upfront.
The problems with a lot of these driving experts is that their advice originates from the track and driving dynamics rather than the risks you’re facing on the road. If you’re driving in the Le Mans 24hr race and its tipping it down with rain, you might very well want your better tyres out on the back so you can hunt out the limits of grip on every bend in 2 inches of standing water. Unexpected understeer and oversteer are simply not a big risk out on the road unless you’re driving like a cock. In 20yrs of driving its never ever happened to me – and I have driven like a cock from time to time.