Yeah, there always that guy who comes late, to avoid the running, or the pushups or whatever we do for warm up. Then like you say, he is lazy during work out, waiting for the sparring. And usually he doesn't understand the world light.
But i think it's also a good training. If you are able to hold your own against a fresher guy, you're in a good path. But it can be very frustrating if the difference in fatigue is huge. If that's the case, and I don't like the person, i can be mean and use techniques i won't usually use... Teeps to the face, heavy drops etc...