Yeah, any time you try to force an antler to fall off, you have to be careful that you don't trap a buck with solidly attached antlers. That's one plus with using bungee cords. They stretch enough to give unlike a solid steel frame or stiff wire and if the device is designed correctly, the ends will slip off before trapping a buck. You'd have to use some judgement when making the part of the trap that the bungees fasten to to get the right release force. I'd tend to go with a low force that would probably mean the bungees would need to be refastened to the frame frequently. Still, hHarming a buck is the last thing we want to do. I like your idea of corn against a log too since that doesn't take any work and the shape of the log naturally forces a buck to bump his antlers gently.