My buddy shot a decent 3 point blacktail before dark. That dang deer busted down the hill, flipped and flopped across the toutle river and fell dead on the opposite shore line. We could see it but couldn't get around to it until the next morning believe me we tried. It wasn't freezing that night, but still pretty cold and the meat was fine. Now another buddy shot a little spike one evenig, near a logging road and we couldn't find him for nothing, looked for hours after dark. Next morning find out that we had been walking circles around him, he had tucked up under a log in some stickers. Again fairly cold that evening, but that deer had deffinently spoiled A LITTLE. Both deer were one shot kills (lung shots), so I think you are taking a chance leaving them, but it doesn't necesarily mean it will be spoiled. Just might not be as tasty as you hoped.
It happens sometimes that you've got to leave them lay, especially if theres a chance it might get up and run....I mean things don't always work out like we plan. Thumping around in the brush at night with lights trying to find a downed animal is easier than it sounds(been there). Especially in this brushy, foggy, rainy, reprod, devils clubbed, slash piled, stream covered, up and down, blackberry heaven in Western Washington. In 20 years of hunting and around some real idiots, never has there been a deer or elk that anybody I know has shot that hasn't been edible.