Didn't the card have a limit?

Literally the first sentence in the article

"The button said approved every time as nobody had set a limit."

Corporate cards often have huge limits. See also https://news.ycombinator.com/item?id=49725666

Many corporate cards (or even personal cards for high-earners and impeccable credit) do not have "limits". At least not limits that will be reached with normal usage.

There is undoubtedly still some balance threshold that will trigger an internal account review and probably a phone call, though.