John, the IG only means that the isolated grounding conductor does not land on anything else before it gets to the receptacle and it doesn't hit the box there.
On the line side it still gets connected to the service grounding system, typically on the bus par where the MBJ lands.
If I was doing this for lightning mitigation, I would land all the IGs on a bus bar, as close to the server as possible so it was acting as a bonding conductor between the server and all of the terminals. Then go back to the MBJ bar from there.
In my pool bar situation here, we actually fixed the lightning problem with a frame to frame bonding conductor from the remote POS terminal to the server, pulled as short as we could get it, with ferrites on the data cable, left long.
We lived with the "ground loop" guys and the "noise" guys all summer, until we pointed out the terminal did not get blown up once or twice a month like it was.
