In their notifications about the new billing system for the Google Maps APIs, Google very clearly state that you \"can set usage limits to protect against unexpected increas
Capping API Usage
Depending on the API, you can explicitly cap requests in a variety of ways, including: requests per day, requests per 100 seconds, and requests per 100 seconds per user. You might want to limit the billable usage by setting caps. For example, to prevent getting billed for usage beyond the free courtesy usage limits, you can set requests per day caps.
For more info, check this doc: https://cloud.google.com/apis/docs/capping-api-usage