That really would suck to lose a well-shot deer just because someone else found it before you did.

Would the person who dragged it out have been trespassing on private property to take the deer, or was this public land?

If I had found it myself, I'dsure like to back-trail it to find the shooter and help him locate his deer, but doing this would risk ruining someone else's hunt by tromping through the woods and calling out.

I would not however, let a freshly killed deer's meatgo to waste just because the shooter was unable to track it down in a reasonable mount of time, as long as it could be obtained without breaking the law.

Lots to consider there that would effect how long I'd wait before considering taking it to make sure it wasn't wasted:
-temperature which would spoil the meat quicker
-rain which may make the trailing very difficult
-type of wound and amount of blood
-coyote population which may chew it up before you get there