Make it a clearly selectable option, explaining both downsides. Be vocal about it being selected if you want to.
But the thought that not immediately reacting to an e-mail can cost me a month's salary or more is terrifying. Maybe it'll get waived. Maybe it'll be waived in the form of credit that I can only spend on the product (i.e. for my purposes, not waived). Maybe I'll be stuck with it. The "maybe" is the danger here.
Let's say I put some obscure 50 MB dataset into a public S3 bucket, and pay my <1 cent per month to host it and like a dollar for each 200 downloads. Rarely does a month exceed a dollar or two, all is good.
Then someone builds a poorly made colab that downloads the entire dataset each time it is run, and the colab hits the front page of HN while I'm traveling, and makes it to social media the next day because it shows something funny. And people don't run it just once, they play with the parameters, running it multiple times.
By the time I'm back and see the e-mail, a 10000 USD bill may be waiting for me.
To obscure? How about this one:
The operator of a semi-popular website has decided to hate me. Each page load now contains an <img src=[my image]?t=[timestamp] width=1 height=1> in the header, pointing to the biggest image I'm hosting for my small static website.
Edit: Even better example
I've accidentally left an API key in a git repo that I pushed online. My carefully set up billing alert was deleted, then my account started spun up as many of the most expensive GPU instances as quota would allow and started mining Monero. In this scenario, I think a $10000 bill would be "getting off easy".
(Just to be clear, these are hypothetical scenarios. If anyone knows how various cloud providers would react to those in practice, or if you know that there are countermeasures that would reliably stop them, please do tell!)
