Admittedly, I'm no trillion dollar cloud host —and I don't know your perspective here— but I'd expect that a trillion dollar cloud host could look at my billing

Admittedly, I'm no trillion dollar cloud host —and I don't know your perspective here— but I'd expect that a trillion dollar cloud host could look at my billing data at an hourly resolution and fairly accurately predict that that'll look like at the end of the month. They don't need to cut me off right away (unless I'm already outside my budget) but for most bitten people, getting a call the day after making a colossal mistake will save everybody a lot of money and angst. Neither of us needs to negotiate and I don't have to sell Grandma. It's been a few years but the last time I tried AWS's Budgets, it took a hundred clicks or so per service to just get an email out of it. Emails get missed, life gets in the way, etc. The cost to a trillion dollar cloud host to call me up is far less than it would cost you to call me as they off-shore it all. And I'm all for people actively choosing to play without limits. I just think a lot of people a) don't respect that from the off, and b) aren't notified in a timely fashion.