Only when BTCs are purchased for USD or some other property that has human value does the BTC become the property of humans.
If this is true, then if a human initiates the sale of the bitcoins owned by the computer, then that is theft and the computer would have been victimized by the criminal human.
Haha true though computers don't have rights under current law. It's an iffy scenario. Of course, one could argue that they own the computer and thus any work done by the computer they own is also theirs. But, it's interesting that then the 'work' is being confirmed by other computers who are also owned by other individuals, but not by the individuals themselves.
Nonetheless, I can write a basic java program to do 'work' as well...such as running a simple script to generate, say, a list of integers from 1-1000 by increments of 2 (i.e. 2,4,6,8....1000). Do these numbers have value? If I mistakenly send this list to another individual (i.e. the product of the work done), do I have the legal right to reclaim it? Mind you, I have no copyright for this list, just as BTCs are not under copyright.