FIdelity Investments: can you allow touchtone-only?

Fidelity, can you add a feature to your system by which a caller can tell it to be in touch-tone mode only? Right now, the system accepts both modes. It's a problem if you're calling from a loud place, such as an airport terminal or restaurant. In that case, the system is always being interrupted because it thinks you're talking to it.

On the other hand, if, at the beginning of the call, a caller can press an option that tells the system, "ignore spoken sounds, and react only to buttons," the problem would go away.

Thanks.