How to switch off the acknowledgement and response requests when creating a transmittal?

I've watched the how to create a transmittal https://www.youtube.com/watch?v=xncDxmTwE6A&index=3&list=PLr0VhGCcjH2onEqat_y5iK6yWsm1FnF8W  and the section regarding scheduling, my question is how do I switch off the acknowledgement and response requests?

When I leave the schedule section blank, people still receive the notifications. Feedback from the team is that this is a bit annoying and nobody is really acknowledging them anyway.

Any help would be appreciated.

Thank you.