Ok. I call BS. What most people don't realize is that the anchor usually does not dig into the bottom to hold a ship in place. What holds the ship in place is the weight of the anchor and the anchor chain piled on the bottom. "Dragging anchor" is something that happens during storms and is a bad thing.
An abandoned anchor would be not attached to a ship and so not dragged, no?
The anchor is always supposed to dig in for good holding.
After the anchor is let go the ship pays out chain until they get the proper scope (usually 7x the depth) and then pulls on the chain to set (dig in) the anchor.
Cables are charted on navigation charts and marked Do Not Anchor.
If a Bozo anchors in one of these spots and accidently hooks the cable, they will bring the cable up with the anchor if the break is not near the anchor. If the cable breaks near the anchor, it can slide off. The best thing the Bozo can do at this point is let the anchor go with the cable and hope he doesn’t get caught. I’ve picked up discarded steel cargo wires in harbors and needed a tug & barge to come alongside & torch the stuff off.
If it was one of those al-kady ships we have heard about and they did it on porpoise, they likely would have pulled up the cable & had to dump their anchor to clear it just like the Bozo above.