Don't you mean "IF vendors added.... etc." ? Or do you know this to be the case? And it is pretty hard/impossible to determine 'intent' as in "in order to boost sales" unless you have emails regarding that.
Also, "I disclosed it" isn't necessarily to admit that 'one knew there were specific known risks.' It could be the case that the vendor was unfamiliar with anything about diketones and once they became aware and checked their products, that they then reported that and changed it.
And what about the consumer? Wouldn't they be 'negligent' along the same lines? You suppose that vendors would automatically know the alleged dangers. Couldn't the same be said about the consumers? Perhaps you could assume 'intent' in their case as well - say, a slow suicide attempt - which in some localities is actionable or at least a moral crime.
But let's - say as with some smokers - they knew about diacetyl and decided to use eliquids with it anyway because of taste. A personal decision that harms no one but perhaps themselves. Can they then later sue a vendor or manufacturer if they knew ahead of time, like many smokers who sued big tobacco? Or do you just want to indict only one side of this consensual exchange?
And since one is responsible for their own health, isn't it incumbent that the person themselves find out all there is to know about any substance they ingest or inhale and see to it that they only buy from vendors who they can either be assured no such substance are present? (which is still only 'faith' in what someone would say or faith in 'lab reports' that they may provide.)
But you might say, 'that's what gov't regulation is for!' Here's a story regarding steve's peanut guy:
"MINNEAPOLIS, Minnesota (CNN) -- The deadly outbreak of salmonella traced to a Georgia peanut plant was fueled by poor oversight by food safety regulators and a slow response by federal agencies, state health officials and outside experts say."
Should the FDA be responsible for the deaths? The FDA head indicted and sent to jail?
The point isn't that, but that the FDA didn't really 'provide the protection' that some think is absolute when done by gov't, and absent when it is done by business, who actually have the most to lose (other than the customers), if their products are tainted. Again, consumers when they have these type of considerations should take it on themselves, since it is their bodies for which they are responsible.
You sound like a lawyer for big tobacco.
What it comes down to is the following. A known risk has been established that can have serious consequences. When the damage is done, what side of history will you be on? I am on the right side because I speak out against the risk and those who insanely defend it.