[mhzsh]

For types of 2FA, sadly. AWS also does it to verify your phone number when you create an account.

[radford-neal]

So the worry is that some fraudster would set up numerous AWS accounts with a number for 2FA which AWS would call, and then they'd ding them for the 25 cent charge?

If actually a problem, having the charge go to charity rather than the recipient would eliminate any monetary incentive. I suppose one is left with someone who has a grudge against AWS trying to bankrupt them 25 cents at a time...