If that's not enough warning for someone then they probably shouldn't have a smart phone, or if they do it should have strict parental controls on it (blocking 3rd party installs, most sites, and phone calls/texts).
There have been many such cases.
The PKI industry is a good example of this.
The Certificate authorities have to abide by standards and any misbehaving Certificate Authorities can be removed.
I'd argue the integrity of the PKI industry is just as important, if not more so, than App Stores and they have managed to maintain a device agnostic market with healthy competition.
I can, and I don't mind. Let it happen. Computer freedom is more important than preventing scams and fraud. Just have the corporations and banks eat the losses instead. God knows these trillion dollar corporations can afford it.
- Ben Franklin