They don’t allow it. It happens. Unless you have someone watching the backhoe in real time with like a stun gun pointed at the operator, you WILL get infrastructure wrecked. The can’t know and care about every wire laid down there, and there are a lot.
Remember, kinder Morgan was off by 40 feet on it’s as-built diagram, which the operator was using to ensure he didn’t spike the pressurized oil line. Since I’m writing it here, you know a geyser happened, coating homes and property downwind.