This seems pretty black and white to me. Dispatching an alreadywounded deer as quickly and cleanly and safely as possible is the morally right thing to do. PERIOD!

Unfortunately in this case, the right thingwould be aviolation in most states. The only grey areasurfaces if a warden shows up. A warden with a sense of sportsmanship, respect for the animal or whats right would let it go.
The Barney Fife type would write a ticket. Given the circumstances, I'd take my chances on reasoning with Barney if he showed up. If Barney was a moron I'd try the judge. Either way, there shouldnt be a question about putting down a mortally wounded animal as humanely as possible.