Don't install apps from back alleyways:
Not really sure naive is the problem. The habits from using windows is carried over I think. Android is in some ways similar to Windows where you can literally install anything from everywhere. Not saying that Windows does not get malware but Windows at least do get periodic system updates and most people install some sort of anti-virus / anti-malware solution. Both of these seem to be missing in many Android phones.
when my teacher didn't know something we would write to Dianna Hacker ask her to answer our confusion.
English / grammar is just an example. Isn't it possible for student who are still confused after a personal finance lesson to seek advice elsewhere? Should we ban all subjective subjects? Literature perhaps?