That is in fact useful information to someone that needs that info, because it means they should never eat it. I think this is a bad example, because I have no idea what you're talking about.

Likely a reference to the recent addition of sesame to the allergen disclosure legislation in the US, and the subsequent rampant over labeling.

Nobody seems to remember a bunch of companies receiving rather large fines for pulling known bull-crap "may contain sesame."