> Switching the engine off in drive or neutral does not appear to lock the steering.
Turning the engine off with the key need not lock the steering, but it will lock the steering if you turn the key past off to lock.
In a run-away engine scenario, are you likely to stop turning the key in a position that you don't use very often? Or, are you likely to turn it as hard as possible?
There may be an interlock that is supposed to keep the key from locking the steering while in drive or neutral, but do you trust it? (What about manual transmission cars? I know that I can lock my steering while in gear. I forget whether it requires clutch-in though.)
Switching off the ignition can lock the steering....
You also lose the power-assist on the brakes.
Given the above, you might not notice that you've also lost the power-assist on the steering.