Hi and welcome!
I can tell you from personal experience that in at least some cases the manufacturers are not lying. I have nut allergies and I often sample packaged foods that say "may contain traces of nuts" or "manufactured on shared equipment." I’ll take a small bite (very small!) and wait between 3-5 minutes before continuing. Usually, I have no issues, but in some cases - the most recent being a package of "slice and bake" cookies - I will have a mild reaction, and I know to stop eating that particular item.
Of course, if anyone has a very severe nut allergy, I don’t even recommend chancing it. It’s simply not worth the risk.
But back to your original question - yes, I suppose it is possible that some companies are either trying to prevent a lawsuit or are being overly cautious, but hey, food allergies can be deadly - better safe than sorry!
I’m curious what other people think about this as well… and would love to hear from someone "in the know" !