This is deceptive because of expectations. When you see two products from the same manufacturer with the same name and same product, you expect them to be the same.

If two gas pumps looked exactly the same but one discretely touted 84 octane (which will typically destroy most engines) would you notice? This happened to me in Utah at a Walmart. Fortunately I noticed halfway through and offset it with a much higher octane.

Expectations are a large part of survival. Once you learn something, you don't expect to have to relearn it every time, but it seems that Act took advantage of this human trait.