Legal Question in Technology Law in California

This happens all the time and theoretically yes, you could be prosecuted for identity theft. I doubt that the bank would become involved in the situation unless there are repeated instances of questionable transactions or the amounts are large. Your best protection would be to get permission in writing (or on videotape) each time, or a power of attorney if she will execute one. If she becomes incapacitated, and you are her closest kin, you could apply to the court for a conservatorship.

Theft of $1,500 will often result in jail time, whether it is the result of fraud or not. That this particular transaction was done via computer has nothing to do with whether you will end up in jail.