I can't imagine why a non-adult business would care. I have no intention of registering my domain.x x x. In fact I could probably make the case that even doing so somehow 'implicates' me as to being part of the industry (not passing judgement, just saying if you're trying to avoid it, then just don't buy it).
I just don't see how it affects a non-adult business if someone squats on their x x x domain. And I'd think that adult businesses would be ecstatic to have their own extension. I'd love to have my extension go from a .com to something industry specific so that visitor know exactly what to expect from my site.
But what do I know. The adult business I think has to play by different rules. the closest I ever got was a really good idea not serving adult content, but serving businesses that have adult websites (a link sale service) but my wife shot it down.