Might it be possible to extend the cooldown if the app keeps receiving power/cadence data after the end of the planned workout? For example, have a 10 second window after the scheduled end where the app keeps listening for power data; if it receives readings above, say, 30 W, it adds 1 minute of cooldown. This repeats until the rider lets the 10-second window expire without pedaling. No need to hop off the bike to click or type a keyboard shortcut.