Many crypto exchanges use OOBA. They too will have to pay up soon! Here is an example from one of the largest exchanges. When you log into your account at Coinbase this is part of the process. You log in and immediately receive this:

2-Step Verification

Enter the verification code generated by your phone ending in +x xxx xxx xx13.

Enter 2-step verification code:

Don't ask me for the code again for 30 days when I use this computer.