Take it one step further. Someone has a target that they are trying to acquire (company website access). So they run a fake contest where the prize is a laptop. The laptop that they ship to the "winner" is backdoored as you have described.
Right, hacker might even target a website that's known to be visited by the targets, hack it, use it for drive by downloads attacks - and use the contest win a backdoored device (laptop,iPad,drive,etc) to cherry pick any targets that have not been compromised.