That's quite interesting. My first reaction was close to Peter's, though I'm perhaps a bit more liberal here...
After thinking about it a bit more, it might not be as "bad" as I initially thought.
Who here has a problem with "balancing the histogram" of an SHO image as a whole? Most of us do that, looks pretty **** if you don't (imo).
So now, if I took a photograph of a smaller area, say just the tarantula itself, what would I do? I would probably try to balance that histogram, or at least that would probably be my starting point. So in that sense, whether I selectively balanced the histogram of that region in a larger image, or whether I took an image of just that region and balanced the histogram, the result in that area is basically the same.
The more I think on it, the more I feel a bit ambivalent about this one... I'm less opposed to it than I originally was, but still...
Maybe it'll become part of my standard workflow :p