The vanilla was a gift (and a much appreciated one) from a traveler who no doubt noticed the minor deception involved. But I’m not sure I would have noticed had I been the purchaser.
The jar holds slightly more than four tablespoons of vanilla, or about a quarter cup. Without the indent, I calculate it would have held about a tablespoon more. So the jar appears to hold 20 percent more vanilla than it actually does. (And vanilla is expensive stuff.)
The label is honest — it says it holds 5 centiliters, which is about a quarter cup. But I think people rely more on the eye than the mental calculation, even if they know what a centiliter is.