From vague recollection - there was some pretty damning evidence when it launched that entire swathes of css were direct copies - not just functional equivalence, but identical class/id/selector names.
(Note: this vague recollection might not have been about the particular WordPress theme in the parent comment, but I do recall looking at one of the early Svbtle WP clones and seeing this)
I mean, to me it looks pretentious and lame and I'd never use it, but it seems like it'd be legally actionable if there was actual copyright violations in the offing.