The Vickers was just as good as the U.S .30 cal. I hardly believe that people were trained to get down when they heard the MG42, first off you don't need to train someone to shit themselves and duck. And secondly that could possibly be one of the worst things, you don't get down and duck if you're advancing. You keep your enemies heads down and advance. Why do you think German soldiers were so good? Because they advanced QUICKLY to cover, they never just hit the deck.
One thing about MG42 crews though, which I thought was quite smart, they used to have two MG42s set up, one loaded with tracer ammo and the other not. They'd test fire the tracer loaded one at night so it could be seen, and they'd fire it above head height so Allied soldiers thought it couldn't be depressed anymore.
Then the other was set up below that so it COULD hit the enemy, the Allied soldiers were advance thinking they were out of the field of fire of the MG 'cos it was firing above them...and by the time they'd realised that another one was hitting them, half the squad was dead or dying.