I respect your opinion Teresa and I'm sure it's based on your personal experience and what you have read.
My personal experience is with native RES turtles in more or less natural conditions and I have read very little. Different turtles from different areas might have different food preferences.
My turtles eat according to their apatite and there apatite for plants is determined by how much high protein high fat animal or plant based food that is available to them. I can predict when my turtles are going to start eating my lilies by what time of year it is and how much I have been feeding them. In the spring they have just come out of hibernation and of course they are very hungry. The more hungry they are the more they will try to eat anything that looks edible unless they find a particularly good food source then they will concentrate on that. At that time of year they are making eggs also which adds to their apatite for protein and fat. If you give them a good source of what they need they will ignore the lesser source and only eat what plants they need to round out their diet.
After egg laying they are also particularly hungry and require extra high quality food to prevent lily eating in my ponds.
After egg laying if I feed them and the fish good there is no lily eating and the bigger turtles seem to all disappear.
What happens is that when they have built up their bodies reserves of fat and protein they go into aestivation which is a summertime light hibernation. They burry themselves in the mud 13 feet down in the deepest coldest part of my pond and don't surface for I don't know how long, probably for days or weeks.
I know this because I have lots of big and little RES turtles and during aestivation time, which is now, if I call them and throw out food for them the big ones all pop up from the deepest part of the pond covered with mud. Then they eat and go back to bed. The little ones sleep less if at all.
My turtles have another way to tell me that they want me to feed them and that is to bite my seed pod bags. All I have to do to stop them from doing it is to feed them. It works every time for years now. If they are hungry they will test out anything that might be edible but if you feed them enough they turn into couch potatoes like anyone else and sleep a lot.
Teresa one thing that may explain the difference in your experience and mine is that my ponds have an abundance of native submerged marginals, from water plantain, a turtles favorite plant food, to water purslane, arrowhead, creeping jenny, spike rushes, spiral tape grass, Chinese water chestnut, square stem rush, cattails and many different native sedges and carex species to numerous to mention. Also three different kinds of snails. I have no idea which of these that they prefer except for the water plantain but I think lilies are a ways down the list, at least most varieties. As Jerry said they definitely have their preferences. My turtles like Carolina Sunset and Ladekery Fulgens the best. Not Colorado so far.
Another thing is that my ponds are basically overpopulated with shiner and fathead minnows. Everybody dies eventually and even though the turtles can't catch fish they sure do scavenge any slow or dead ones. That makes for a constant supply of VERY protein and fat rich food source. Fish tend to die after a good feeding for some reason and the turtles pig out on fish food and fish and go to sleep.
My situation is very different than yours and Jerry's and advice from you guys might apply better to most peoples pond situations.
My opinion is that a stuffed turtle will leave lilies alone for the most part.
Jerry I think that sand is the last thing that a RES wants to lay eggs in. They want clay dirt. Sand indicates water flow which is what they are trying to get away from. They also want elevation. I would put as high of a mound of clay dirt in your wire cage area as you can get to the point of leaving only enough fence at the top to prevent escape. And make it packed and very steep right down to the waters edge and plant it in lawn grass seed to prevent erosion and muddy water. An almost flat top and very steep sides is what you want in order to maximize the high egg laying area. They can climb very steep sod. Turtles prefer sod to make their nests in anyway. Mulch it with grass clippings to prevent erosion and muddy water until the sod grows. Turtles also like to be high above the water they slide into so they can see around the area to spot danger. I would make it Turtle Mountain instead of Turtle Beach.
