Someone may register in point A (Home) but is in an area south by 50 miles, so if there is a notification in that area, they would receive it.
In the IPAWS system this may happen, but not in CivicReady. We do not monitor a user's geolocation for a message unless the user responds with their location. If a message goes out over IPAWS via CMAS/WEA, the system sends the message to cell phones within a geolocation. The IPAWS system selects the cell phone tower locations.