I have been feeding my rack with "2 prong" 230V for many years now, and I've always ran lots of kit (the pile emits real heat!) and my family's still alive I'm happy to report...
I don't know the US situation, but here in Holland the builders often bore the ground rod only 2m deep, which is NOT a good low resistance earth at all, this leads to stray voltage across the earth connection.
What I mean, it's better not to use earthing at all than use a faulty earth...
OF COURSE THE ONLY REALLY SAFE WAY IS HAVING A GOOD EARTH AND EARTHING YOUR GEAR !!!
Barend