What was the perceived risk if she accidentally drank non-high heat treated cow's milk prior to this reaction? Hypothetically speaking, of course.
I'm not a lawyer, I'm not even close to one but what pops up first in my mind is the concept of
innocent misrepresentation. Innocent misrepresentation is one of the three recognized varieties of misrepresentations in contract law. Essentially, it is a misrepresentation made by someone who had reasonable grounds for believing that his false statement was true. So in the above example, if the seller didn't know the stereo was actually old, he would only be liable for an innocent misrepresentation. In the real world, however, it is often the case that because the other two varieties of misrepresentation (negligent and fraudulent) are much more difficult to prove (because of the complexity of proving intent), often this is the only course of action left available.
What Constitutes Innocent Misrepresentation?
There are five elements that must be satisfied to prove innocent misrepresentation:
*Someone must makes a false representation (that must be false at the time of the transaction, AND remain false. If it turns out to be true later on, there is no case.)
*The misrepresentation is "material to the transaction," which means it must be about an important element of the transaction at hand. If you are selling a car and say that it has 15,000 miles on it when it actually has 15,124 miles, this would not be a material mistake.
*The other party must substantially rely on the lie. This means the other party not only must go through with the transaction, they must do so only because of the misrepresentation. If the buyer, for instance, would have bought your item regardless of what you said about it, this does not count. They must substantially rely on the falsehood.
*The lie must also proximately cause the other party to suffer damages. In other words, the buyer must be actually harmed by the final transaction in order to sue.
In addition to those four elements, which are necessary for negligent and fraudulent misrepresentation as well, there is a fifth element that is unique to innocent misrepresentation.
*The loss of the one party must benefit the other. This is an odd and very vague requirement, but one that the courts have held up nonetheless. Essentially, if the misrepresentation made does not benefit the person who made it, (or hurts BOTH parties to the contract), then the courts will not consider it a case of misrepresentation. Just exactly how the court will measure if a party has "benefitted" from a lie remains indistinct, and various states interpret this rule differently.
For clarification's sake I am not recommending anyone with an IgE-mediated life-threatening allergy take a risk beyond their known, personally derived risk-benefit calculus. This is simply how, if I were to hypothetically argue for reimbursement for medical damage, I would take on that argument.
Now for the other side of the coin. For the sake of argument let's say negligence, fraud and social responsibility are off the table in order to take a look at a lower standard of innocent misrepresentation which doesn't include proof of intent as per the cited text. Is it correct? Dunno, not a lawyer but working through the logic nonetheless.
Could the conditions be satisfied? Possibly. Can you prove it? Probably not. How would you demonstrate the barista did not make a soy latte? How would you demonstrate the latte was not soy based but merely contaminated? How would you demonstrate that the latte represented as soy was not taken by another person, meaning a mistake made between customers and not service? How would you demonstrate it was milk that induced the reaction and not another allergen? And that's not even delving into communicating known risk to server.
So that's both sides from my limited perspective. In a way I see OP's situation as unique because the customer wasn't seeking a guarantee of "free of" but to consume a product that was materially correct/true with the understanding that likely contamination was always present, medically tolerated historically and therefore acceptable. Although FALCPA wouldn't cover this instance that somewhat correlates to the initiation of a product recall. Shared lines are not revealed, contamination is expected, but undisclosed ingredients, gross contamination or mistaken production/labeling of top 8 have all been catalysts for recall.
I want to point out one more item re: OP's situation and risk. According to conventional wisdom DD was following exactly what is promoted top-down from medical to the FA community. Only avoid what you must, live a normal life, take your chef cards and use some basic precautions, rescue meds in case of accidental ingestion, follow EAP. In that context how exactly is OP's DD not going by conventional medical wisdom? Just because it didn't work out in one instance doesn't mean she wasn't following status quo.
Now that has zilch to do with Starbucks as a corporation but remember they are not only a food service but also have a line of manufactured items. At what point should they have a different standard for in store food service than their boxed manufactured products? I would argue where the production is not dedicated and supervised but individualized real time per instance and highly varied as per the in store experience is. But still, why do we listen to allergists when it comes to food manufacturing anyhow? How much should their recommendations on how to examine risk factor in? Do their quality of life studies accurately reflect reality?