Hi Martin,
I've seen issues before with large companies as well, and there is seemed that Google was using the IP address to see if a limit of 2500 requests was made. But that was not with a Mendix app. So I can't confirm, perhaps someone else can.
You can get a free API key to use Google Maps: https://developers.google.com/maps/documentation/javascript/get-api-key.
When you have the API key you can add it to the Google Maps widget at the following page:
A description about the Google Maps widget for Mendix can be found here: https://github.com/mendix/GoogleMapsWidget
Hope this helps.
Edit: I see that the GeoCode.java from the Google Maps module is not using an API key for the request.
Edit 2: Download the latest Google Maps module from the app store, https://appstore.home.mendix.com/link/app/174/Mendix/Google-Maps-Module. Now it provides a constant for the API key.