I do alot of hunting on the ground and have been busted a few times. In fact the deer I shot last year busted me. I think he caught some slight movement but it didn't scare him to bad. He started trotting off and after I was at full draw and settled I made a slight noise and stopped him. Let the arrow fly and that was it.

I have had bucks bust me while letting down though. I draw and then they always seem to stop in the wrong spot and stay there for 5 minutes. I hold as long as I can and then have to let down. That really sucks.