API Hourly Limit

I've been wondering for a while now, does the API hourly limit of Danbooru enforce itself through throttling, or capping?

That is, does Danbooru make sure you download roughly 3,000 images per hour (if you are a free member) by throttling you to make it so, or will it outright refuse to serve after you have reached the hourly limit?

Images have nothing to do with the limit. The API hourly limit only applies to the API, meaning pages with .json or .xml formatting. HTML pages and images have no limit as far as I know.

To answer you question: Once you have reached the limit, the server will refuse your API requests completely until your limit resets, giving "421 User Throttled" in place of actual results.