I don't know, I don't trust the banks though. All I know is that some require one to use a firewall and some even provide their own security software. I suspect they are only thinking in terms of desktop PCs but the day they need to dispute with you is the day you find out how unreasonably officious they can get. If the bank has an app written by them, you probably have a good case. Access through the browser however and I suspect all they will say is that they only support devices with firewalls, as per the fine print. Just a guess...