Users tend to think it’s safe to install apps from Google Play. After all, it’s the most official of all official stores for Android, and all apps there are thoroughly vetted by Google moderators, right?
Bear in mind, however, that Google Play is home to more than three million unique apps, most of which get updated regularly, and to vet all of them thoroughly — that is, really thoroughly — is beyond the resources of even one of the world’s largest corporations.