The Diary page will always include a red dotted line going vertically from top to bottom to indicate the exact point of service at the time you looking at the page, to quickly see what stage your bookings and walk-ins are at, in live service.
A handy warning to show any bookings that have 15 minutes left will have a red outline around them.
This quickly allows you to manage expectations of walk-ins and at a glance, allows you to see which bookings are due to leave soon.