Being fair, I have to help people that didn’t install from third-party stores or side-loading that get hit with apps that basically keep popping full screen ads and fake infection warnings. So many bad/scamy apps are in the official Play Store. It is possible that some of the spam apps somehow hide the prompts within some of the ads to enable installing from unknown sources in order to side-load more. But Google should be putting all the effort to stop users from using apks and third-party stores into getting their own house in order.