How to handle stray map markers

This map is trying to show available listings in Austin, TX. A few rogue map markers is causing the map to zoom out to include all markers on the map.

Listing addresses are geocoded to get the correct latitude and longitude. Sometimes, especially when the address was not correctly input by the agent during the creation of the MLS listing, that geocoding goes awry:

Detecting that the geocode didn't quite give us what we expected isn't so easy.  The geocode succeeded, we just got wrong results.

Rover IDX can handle this scenario very nicely, using the polygons feature.