That's an interesting and useful idea but it's not appropriate for Maemo Mapper because MM is an application program not a system program. MM shouldn't be responsible for system level actions like choosing a WiFi access point.

There's a way to do that and let MM remain strictly an application program. Suppose there were a number of ways for MM to signal that it's near a particular POI or class of POIs, such as play a sound, pop up a little window that describes the POI, or run another program. You could choose to have MM run the "Select Connection" program.