I send “What did you work on today? what are you working on tomorrow?” Every day at 4:30pm.
Not as a proof that we’re earning our keep but to keep track on all the unplanned stuff and to keep our eyes on the planned items.
I also track everything I'd put into my update in Workflowy (and more, sometimes) throughout the day, so I end up with a bunch of daily logs to look back on if needed. I use it a lot, especially for our longer-form written "end-of-week" updates.