We had a similar problem with mobile search ads. The vast majority of clicks we got were misclicks, which is very painful when you're bidding $5+ click. We fixed the issue by putting a -90% bid on mobile ads. Now once every few months someone from Google calls us and tries to convince us to remove that -90% bid, assuring us the traffic is good and will convert. Pretty sleazy.
In our account penalizing the bid for mobile ads didn't help because it looks like Google treats 'mobile' and 'tablets' separately. So we prevented ads on phones, but you can't penalize the bid for tablets so that doesn't work to prevent games on iPads.
The Google support person told me they can't tell the difference between tablets and desktops, but I don't believe that for a second. Our own analytics clearly showed the user-agent for all of the visitors was for tablets and not desktops.
The Google support person may not be fully informed, but they are provably incorrect in that claim.
Simply put, Google used to offer the ability to include/exclude devices based on desktop/tablet/mobile device types. Additionally, they offer the ability in their device segment reports in the AdWords UI to see what device did what. They have the data.
When Enhanced Campaigns were launched in the not so distant past, there was a large uproar from the paid search community (of which I consider myself apart of given my search agency background). It was very much a sense of them forcing mobile traffic despite our wishes and the negative bid modifier for mobile was something we had to push them on.
At the time, Google took the stance that tablet traffic/usage was largely indistinguishable from desktop traffic, so it shouldn't be a problem to blend those. Anyone with half a clue in this field could point out several reasons why that was false, but we were unsuccessful in getting that changed.
There have been a few changes to AdWords targeting and settings in the past couple of years that were pretty large steps back for savvy advertisers, and this was one of them.
Isn't it also the case that you can restrict your ads to Google search only which should avoid these in app ads? Or are you looking for placements on the display network as well (or only)?
awhile back, google decided it would be better to ram mobile traffic down your throat. ie when you buy from them mobile is included by default. thats not to say that mobile won't do well for you. you'd be best served to separate this. on the google content network you'd be better served to create specific placements instead of using keywords. especially in your case. you can get good traffic from the content network it just takes a bit of learning/tweaking.
