[drfloyd51]

See also: Why is the default cap so low? I lost €78bojillion because my API stopped working.

[Barbing]

Demand on-call phone numbers, autodial the entire company when it looks like they’re about to lose their first bojillion.

No, you don't really have to give Google a bunch of phone numbers. The input box will also accept entry of the following text:

“I'm a big stupid idiot, and when my API stops working, which it will, it will be all my fault and not Google's.”

[jamespo]

Monitoring could pick this up in minutes rather than how long this took to discover

[drfloyd51]

Monitoring could have detected overspend as well.

My point is either choice, caps or no caps, has its cons.