i am Mr.Bang in game and i am recently came back to play in Milan (IT) since years without even downloaded the app.
i've noticed that the amount of fake gps player is bigger then even and i have a working suggestion.
for 3 weeks over 6 fake gps played in our cell and they always used viruses.
Long story short they get lv4-5, they redeem the ingress code with the virus inside and then fly over the portal and use it.
i red around the internet that this is the main fake gps/flyers attacking procedure.
my suggestion is to make that all the codes (or at least the one with viruses) are not redeemable until you reach lv.8.
i think this way the flyers will get discutaged to make every fake account at lv.8 every time they want to attack illegitimately.
i hope you will consider my humble suggestion.