These warnings are worse than useless. Since they usually don't actually name the substance, let alone quantify or contextualize the risks, I have no say of using the information.
If I see a warning, it could mean that there are harmful, odorless chemicals being emitted by some manufacturing process. Or it could mean I'm near a parking facility. Or it could mean they're serving alcohol somewhere in the venue. There's a huge difference between those three, but the warning posted is identical.
They're worse than useless because they actively desensitize people to actionable information by overloading them with unactionable information.
If I see a warning, it could mean that there are harmful, odorless chemicals being emitted by some manufacturing process. Or it could mean I'm near a parking facility. Or it could mean they're serving alcohol somewhere in the venue. There's a huge difference between those three, but the warning posted is identical.
They're worse than useless because they actively desensitize people to actionable information by overloading them with unactionable information.