You can't have everything. I personally side with a device I can modify. I think generally in Android there are enough warnings (those with timers and large "S

You can't have everything. I personally side with a device I can modify. I think generally in Android there are enough warnings (those with timers and large "SECURITY RISK" warnings that are difficult to ignore) when enabling side loading, and also going out of the way to download malware apks in the first place, that the number of affected users has to be quite low. And you can have default on malware scanning too (which I believe Google Play does). Also you can malware scan before install as well. I think this is low enough risk that the benefit is greater than disabling it entirely. Same could be said for allowing root and different OS install. I could install something very insecure or make bad choices. But then I want to have that choice, and I think it shouldn't be so easy that users would just do it by chance. We need to remember there are other social engineering attack vectors against the most secure systems (like asking for passwords, or even asking to lend the phone and so on) too. The attacks I hear on Android users recently mostly seem to be related to hijacking SMS auth and so on -- I really don't believe side loading has proven to be a large security issue at all (or other OS images for that matter). In fact I think they should be making installing alternate OS images and alternate app store easier, if Google wants to earn my vote of confidence (at least as far as Android goes) :)