Some boat GPSs have Anchor Drag Alarms. Also useful for Man Overboard situations. One sets a waypoint when an anchor is dropped. One enters a distance or radius from that point equal to the length of chain on the anchor. If the GPS observes a lat-long outside that radius it sounds an alarm as the anchor is likely dragging.
I have seen mention of "Proximity Alarms" here and on non-Garmin sites. On the Garmin Instinct can the proximity to a waypoint alarm be reversed to sound when one exceeds a distance from the point?