I missed a check-in by accident

Hold the switch. Checking in during the grace period means no alert is sent. If an alert already went out, checking in sends a signed all-clear to everyone already notified.

If contacts were alerted

They see that you have checked in. You may want to message them directly. If an alert ended without a trusted check-in, they are told to check on you another way.

Avoid it next time

• Turn on notifications so you get the reminder before your deadline.
• Lengthen the grace period.
• Use quiet hours for sleep or work, or switch to a repeating window.
• Pause for a flight or no-signal trip.
• Move a key shortcut under the switch so it is one tap away.