Geocoder it very "limited" feature, so admin should be warn that better use "lat,lng" instead of just a Address, 
or better solution it use Server Side Geocoder: try get coordinates in time save the module options, and store result as params.
```php
$req_url = 'https://maps.googleapis.com/maps/api/geocode/xml?sensor=false&address=' . urlencode($address);
$xml = simplexml_load_file($req_url);
if($xml->status == 'OK'){
  //save it
} else {
 //show error message
]
```
after it can remove Geocoder from frontend with all alerts ;)