some bad info here i think so perhaps this will help.... a two wire cord has a ground??? yes it does... one wire is the ground the other is hot... there has to be a ground to reference to !!! no ground?? no voltage... the third wire is a safety... it's purpose is to carry the extra voltage to ground quickly in the event of an extreme failure.... the purpose of a ground lift is to get you through the job without tracing the problem which is the correct course of action... but you'll be better able to do that when the clients gone... IMO...
Thanks for the input demented. I think we're confusing terminology here. I was under the impression that, in a 3-prong system, the hot wire (usually the small flat prong) is called the "hot" or "live" wire, the return (the bigger flat prong) was called the "neutral," and the grounding connection (the round prong) is called "ground" or "earth."
I understand that usually current does not flow through the grounding connection (the round prong), and that it's there in case something shorts in your equipment, placing high voltages on enclosures, mics, etc. When that happens, the grounding connection steps in and provides a safe "backup" place for the current to return to ground.
But I think your last comment answered my question. Though I think you're talking about in the recording environment (I actually had gigging with an amp in mind, but since this is the HR board, your thinking makes perfect sense), the principle's the same. It's not safe, but it is a quick fix.
So ... if a venue doesn't have a 3-prong outlet (I don't know if there are any like this anymore, or maybe someone's handing you a power strip to plug into with only two-prong receptacles), are you basically just screwed out of being safe?