They SHOULD be on separated infrastructure. Sometimes your separated infrastructure is not as separate as you think. True story. Northwest Airlines (prior to

They SHOULD be on separated infrastructure. Sometimes your separated infrastructure is not as separate as you think. True story. Northwest Airlines (prior to merger with Delta) was grounded for a couple of days in the 90's due to a backhoe cutting through their data and communication lines about 300 yards from their control center. Both vendors were using the same utility right of way. So separate systems, separate vendors, separate cables buried in the ground next to each other. One backhoe operator took them both out.