Apk downloading from App's offer wall

I am having an app on google play and having an offer wall on the same app containing different apps campaigns on CPI basis. I get these apps from different agencies with daily install capping for each campaign. Once this capping gets over these agencies redirect some other campaigns on their same tracking url on my open traffic and those redirect campaigns could be apk campaigns. So I have few questions:-
1) If an apk is downloaded from my Google Play App what could be the consequences ?
2) Does google know about the same ? If 'Yes' than google would blacklist my app and my ratings which I gain in last few years ?
3) How can I prevent the same if this apk downloading from my App is killing me ?