Hi Carlos.
Thanks for the quick response. We've certainly told our clients historically that, while bounce rate is something to bear in mind, it doesn't impact rankings and on certain pages is the only real outcome (depending on what the page is aiming to achieve).
But the more I read, the more it implies it is a stat that can have an impact following the various Google quality algorithms - and I see this video is from 2010, so I'm guessing the situation may have changed by now?
As for the link to the tutorial on spamming, very useful, I'll look into where they're coming from.
Assuming there's no impact on either organic or PPC, I'll set up a filter and leave it at that - but it would still be useful to have a best practice way to send this traffic, if it's real, to the proper geographic site.
Nick.