I'm sure some folks do steal other people's deer. I've unfortunately met more unethical hunters than ethical hunters (in person). Deer theft happens most assuredly. But it can also be an accident.

I was rifle hunting whitetails with a friend. I drove toward his stand and he shot a decent buck. Dropped right where he shot it. He field dressed it (it's how I first learned) and then we noticed that there were three holes: an entrance and an exit that fit with how he shot (angle, side, placement, etc.) and then another chest shot. It was further back, probably clipped a lung.

He had no idea that it was wounded when it approached his stand. He had no way of knowing who had first shot it or even if they were tracking it. We had not heard any gunfire that morning that sounded close enough to be of interest but echoes can be deceiving.

I don't think he stole anyone's deer. But there may well be someone out there telling a "stolen" deer story about that buck.