They were already running their status site on Heroku prior to the last major service outage.

This is correct. They needed ~90 dynos to keep up with about 500 qps on their status page in the last outage.

Source: http://news.ycombinator.net/item?id=4524489

Should probably throw a Fastly or CloudFlare cache in front of a single dyno.

That would suggest people in charge know what they're doing.