A Book Thinks "Mistake Proofing" is "A Six Sigma Tool"

From a seminal "Lean Sigma" book (click for a larger view):

Lean Sigma people have this bias that Six Sigma is the only methodology that can improve quality.

The bias comes out when mistake proofing is referred to as "a Six Sigma tool."

Toyota would beg to differ.

Mistake proofing ("poka yoke" in Japanese) is arguably the FIRST Lean or TPS concept that Toyota introduced to its own company. It's a core Lean methodology.

You can do Six Sigma and also do error proofing, but it's silly to think mistake proofing is "a Six Sigma tool." Good grief.

An additional thought -- real mistake proofing would prevent the error from being MADE, rather than just preventing it from being SHIPPED.