I got busted opening day when trying to draw on a doe. A small buck had come from behind me that i didn't hear or see and was watching the whole thing, he then snorted and took off and that was the end of that hunt. I got busted several more times through out the year as well. I know they didn't see me move because i had my eyes on them the whole time so my guess would be they scented me and i don't have to say what happened next, snort snort, stomp stomp, bye bye, game over!