These stories are a lot different from my experience. For many years, I put most charges on my Visa card, and only ran charges of about $2,000/month on my Amex.

Then, I started accelerating my spending rapidly, figuring at some point they'd call me. Within a few months, I was racking up $20K/month consistently, no problem. Then, I needed a temporary increase to $85K one month, and they approved it, contingent on having a conference call with my bank the next day (in the meantime, they authorized the payment to the merchant).

I was quite impressed. Looking at my credit file, I find no record that they have checked my credit in the last 2-3 years-- so I suspect they have some other way of monitoring U.S. credit risks that doesn't show up on my credit report.

With respect to posters from some other countries, I know that in Hong Kong they tend to be much more cautious. As I understand it, the problem is that HKG doesn't have anything like the centralized credit bureaus that we have in the States. So, a lot of the time, they're sort of flying blind when they are making credit decisions.