PJ,
At the risk of taking a slightly different view, I'm not sure it represents a significant safety risk. Presumably it will not be uncoiled, but all coiled up in a large flat pile. Yes, fishing line could get entangled in it, but that's true of most any structure. Also, I'm assuming, if placed in a pond, it will be marked from above with some sort of buoy. A two foot tall, 10 foot diameter circle would make a nice area of permanent structure.
As a CE, I'm sure you can better evaluate the safety risks than I...but heck, I've put worse in my ponds that has made fine structure.
