What domains did you use in your "experiement"?
Just wait a couple weeks and you'll see that domain you blasted back where it was before you blasted it or sandboxed for a while before being re-entered into the SERPs. I've done experiments like this in the past using xrumer and results were not pretty in the long term. Just sayin'
Whitehat > Blackhat
Period.
Of course I'm not gonna tell you the domains, I already mentioned that.
And I want to point out something to you. You sell some so called white hat SEO service, right? Now off site SEO is all about link building. What methods do you use for that? I think, they are Blog commenting, social bookmarking, web 2.0 properties, article submissions, right?
The black hat SEO we are discussing here is mere automation. What takes 1 hour manually is done withing 5 mins using various tools. What's the harm in that? You just have to maintain some steady rate of building backlinks.
Black hat SEO can be really dangerous when you do it on your site (on site black hat SEO), like keyword stuffing. But off site black hat SEO is never that harmful because, come on, do you have any control over who links to your site? No. Just you don't want to make it too obvious for Google to catch you. Multi level buffering helps a lot here.
Though I don't say its 100% safe.
But please, just show me one site that has got sandboxed due to a scrapebox blast. Please. And be honest on this.