Negative CTR attack from 'unknown region'

I think one of my sites is experiencing a negative CTR attack. Basically I have been looking at my Webmaster Tools and noticed my CTRs dropped for a bunch of keywords I was scoring highly for. I'll put an example word in just to explain, the keyword is not the actual keyword but the stats are correct but for a diff keyword:

'Keyword' e.g. betting tips 19/11/2015
Impressions 648
Clicks 118
CTR 18.21%
Position 2.3

20/11/2015
Impressions 1400
Clicks 165
CTR 11.79%
Position 2.3

You can see the day after had a big spike in impressions but not clicks, the CTR went right down and this happened across a big bunch of keywords that i was scoring highly for.

Looking more deeply into the stats I found the makeup of the stats, broken down by 'country' in Google Webmaster Tools were as follows:

Unknown Region - Impressions 864, Clicks 0, CTR 0%, Position 2.1
United Kingdom - Impressions 601, Clicks 139, CTR 23.13%, Position 2.1
United States - Impressions 212, Clicks 3, CTR 1.42%, Position 3.5
Canada - Impressions 57, Clicks 24, CTR 42.11%, Position 2.7
Australia - Impressions 45, Clicks 21, CTR 46.67%, Position 2.5
Ireland - Impressions 21, Clicks 16, CTR 76.19%, Position 1.1

there are loads more but I won't bore everyone with it. Basically, my stats for 'real' gambling countries are fine, but I seem to be getting a ton of junk/fake traffic from 'unknown region' and US traffic that is blasting me and making my overall click through rate suffer, for individual words and generally site wide.

Do you think Google will be clever enough to figure this **** out, or am I to predict that my site is going to tank in the rankings once the effect of this negative CTR attack kicks in?

I guess this one might be a bit techo geeko for some haha. But I guess the wider question also is do you think search engine Click through rate even has an effect on ranking? There are various debates about this going round at the moment.

Is it likely that what you are seeing here is a general hit on the keyword by bots scanning the rankings - and therefore not clicking on ANY of the terms?
There are a lot of US hosts (AWS, XLHOST etc) that run bots, and typically when I see 'Unknown Region' it's masked bots.

Will it have an effect on rankings for a keyword? Well it might I guess as Google MAY take it as a signal that none of the results were desirable to the searcher (as it's unlikely any links were clicked).

But Google are typically smarter than that and know how to pick up ranking bots I think.
8-)

To just give a little more history to this 'attack', the massive amount of hits from 'unknown region' only started on 10th November.

The stats before that were no more than 10 impressions each day from unknown region and that was consistent going back months, but on 10th November that spiked to around 350 per day and the most recent day in the stats (20th Nov) had 723 impressions from unknown region with 0 clicks.

Yeah could be a bot and even an SEO tool - something like scrapebox that can be used by SEO's to mimic search engines. It is often used to collect data on keywords and find websites that rank for those queries. It can search thousands of times per hour and hence inflate impressions. Companies are also starting to build software to monitor PPC activity on high profile keywords, again this can inflate impressions, because they too must monitor and often mimic searches.