I'm going to have to disagree to an extent as well. While I dont believe a deer that is walking through is as alert, when I call a deer in he will look all over the ground for what made that sound and if nothing is present his eyes go to the trees. I would say this happened to me this year ATLEAST 3 or 4 times. They got called in with a rattling sequence or a grunt and they came to the vicinity and looked for a few minutes. When they saw nothing on the ground they started to scan the skyline. And everytime they picked me out (it was actually most likely the tree stand) and stared for a second. Did they bolt and go off the other way? Once, the others no. But did they know something was up? (Pun intended) Yes they did.