[jaylevitt]

I think (I assume) his point was that when you have a complex system that's growing rapidly, it's difficult to predict what the next breaking point will be. Building in extra load gives you a window of opportunity: You discover the breaking point, turn off the extra load, re-engineer, and turn back on the canary so you can find the next breaking point.

In theory, you'd think you can do load-testing and simulations and capacity planning, and find these breaking points ahead of time. In practice, it's not always feasible, and this seems like a simple-enough hack that gets you much of the way there.