atm machines, crime, and the lily burk killing

Maybe I'm missing something here, but in the light of Lily Burk's tragic killing, this suggestion from a letter-writer to the Los Angeles Times makes a lot of sense:

To help future victims forced by criminals to withdraw funds from ATM machines, I call on banks to offer the option of a customized emergency personal identification number linked to debit and credit cards. These would allow cash to be withdrawn but would also trigger a silent alarm.

Evie Tole
Rancho Cucamonga