I don't mind cross-posts of topics, given a bit of time to develop, that go unanswered. But posting on multiple sites minutes apart is pushy.
Every once in awhile, this happens in my "real" job. That is, someone e-mails me to ask a question; I follow-up with a colleague in another department, only to find that they've been independently asked the exact same question. When I ask the OP why the shotgun blast approach, they invariably say they wanted an answer quickly and didn't realize I regularly collaborate with person X, Y, and Z.
Seeing that nearly all HB members are CG members (though not vice-versa), long-time members agree that it's best to not split discussions across multiple sites. Consider, for example, if you posted the same message on HB, CG, alt.coffee, s1cafe, CoffeeSnobs, TooMuchCoffee, Coffee Forums, etc. You would get a broader response and more quickly, but those members who belong to multiple sites would rightly feel like they're being spammed. In today's increasingly connected world, it's more likely to happen.
I understand that it's a matter of netiquette and there's room for interpretation. However, if you want to be a member of this site, I ask that you respect the site's goal to "raise the discussion level". On the other hand, if you prefer to frequent a site that has less stringent posting guidelines, I won't be offended.
As for your concerns about advertisers, they are very well aware of the site's policy as expressed in the
Guidelines for productive online discussion. If they have an issue with the site's policies, believe me, they are not shy about telling me!