I can one up her sneaky by a mile on marking a pile my friend , we used really light small pieces of natural wood ,3 inches or so long
and varnished them ,tie it to the pile when you sink it and give it about 5 to 6 feet of extra 20 lb. test mono so later lake levels don't mess with ya .
"Spot Hunters" will find other markers quickly on piles like bottles and such ,but NOT a one ever noticed my little sticks ,was taught to me by a great crappie angler WAY BACK when and can't even remember his name anymore
sure enough made me look hard at any floating sticks in my travels after his advice