A band's booking diary could connect each enquiry to a date, venue and conversation. It should distinguish an initial enquiry, a temporary hold and a confirmed performance so competing requests are handled consistently.
Deposit records need to show what has been requested and received, alongside agreed payment dates. The diary could record which musicians are required and whether their participation is confirmed. Private financial information should not automatically be visible to every performer.
Test two enquiries for the same night, a revised quotation and a date change after payment. Keep accepted terms and important changes together. That creates a clearer booking history than a calendar entry alone, without pretending that every unanswered message has become a sale.
Related reading: ListnIN: How a Live Music Streaming App Connects Artists and Fans.