The VV defence came about thus:
Someone once infamously landed on a platform without clearance and the radio operator asked him to identify himself, to which the reply was: if you don't know who I am then I'm not stupid enough to tell you. And then he took off again.
So if you land without a clearance and they don't know who you are, don't tell them anything, and make a rapid exit before anyone can get an eyeball on you.
Mind you, that was the good old days, you probably wouldn't get away with it these days.