I personlly butcher my own venison so I can have boneless cuts of meat(roast, steaks, chops and trimmings). Most butchers just cut the meat like beef, bone in, and as we know venison is not beef and needs to be cut and trimmed differently.
I have no problem with butchers, but I am not happy if any of my meat gets mixed with someone elses. I am not as worried about desease as I am these guys riding around with their deer strapped to their vehicle showing off all day. NO THANKS. I take extra care from the time the animal is killed and field dressed to the time it gets in the freezer. It wouldn't make sense to take a nice doe or young buck only to have it mixed in with a rutted up buck that was run for 10 miles then improperly cared for.
It is not that hard to make sausage and burger, but if you prefer not to I like whitetail1's suggestion.