The ads weren't only displaying in the app, they were appearing over other apps. This is something that simply can't happen in iOS. How does a standard user kn

The ads weren't only displaying in the app, they were appearing over other apps. This is something that simply can't happen in iOS. How does a standard user know whether a small app to e.g. manipulate photos (as in this instance) is going to be updated a few days later to show ads when it's not running? Shouldn't an end user be able to trust Google's app marketplace to not feed them junk like this?