This sounds a lot like "an old guy's excuse".

If you are 60 years old, you learned how to monitor your spending in the late 1960s.

Same skill here.

Best way to prevent that is to set an account billing alert that will SMS you if your bill goes over $X dollars.

I doubt this feature will ever be implemented, as trying to provide some kind of real-time spend is extremely hard, especially when there are 100+ service bills that need to be aggregated, which usually is a batch process where these things get resolved.