I issued a ticket about this, Vignesh Ramakrishnan was kind enough to reply, but I'll write this here too.

I want to develop an app for my friend's small business that will store and display video/audio files in the 10s of GB. And I'd like to use Digital Ocean to serve the media files. However, I'm worried if a piece of content goes viral, and starts receiving 100,000 x downloads, my friend will be stuck with a large bill. Perhaps a rare edgecase, but this scenario is on my mind.

So I want to propose some kind of simple-to-implement bandwidth throttling. I.e.
if more than x 1000GB of out-data, suspend service.

AWS S3 seems to kind-of have a solution. But the solution is quite involved:
https://stackoverflow.com/questions/39473419/limiting-amazon-s3-downloads-service?noredirect=1&lq=1

I think It would be nice if a service inplemented this in a more convienint mannor.

Thanks!