Having worked in a consumer mass production development company that uses I2C a lot I can assure you there are other ways to ensure that a design is not "borderline buggy". No one in their right mind would even consider loading an I2C bus with so many devices that you run out of address space. A good logic analyser is going to show any "borderline buggy" problems. The only problem we ever encounter with I2C was with multi master buses being driven by an FPGA, and that almost always turned out to be subtle errors in the third party FPGA libraries.
We made at least half a million of each design. So there was plenty of variation to show up anything.