Well, the same you do with Credit Cards or other forms of electronic transfer of debts.
In most banks you must first authenticate your smartphone app by going to an ATM where you use your card and some sort of biometrics to authenticate along with your pin. The app can only be used after this first "machine" authentication.
There are also customer-customizable limits, the usual anti-fraud controls. Of course, there is a lot of scams involving people with less instruction, but it is not substantially different from the levels in other types of transfer/payment.
In most banks you must first authenticate your smartphone app by going to an ATM where you use your card and some sort of biometrics to authenticate along with your pin. The app can only be used after this first "machine" authentication.
There are also customer-customizable limits, the usual anti-fraud controls. Of course, there is a lot of scams involving people with less instruction, but it is not substantially different from the levels in other types of transfer/payment.