With respect, I don't see the relevance because the additional emissions caused by removing a catalytic converter are an extremely minor harm to the occupant and others. If, for example, driving a car with a catalytic converter removed caused the vehicle to explode killing the occupants (or any other significant harm), then the manufacturer and retailer would absolutely be held responsible. Physical products are required to fail safely in foreseeable circumstances.
If by my second point, you're referring to circumventing the tamper-proof seal on medications, then maybe you'd like to expand? Manufacturers, retailers, and medical staff are (jointly) responsible for medications for their entire life cycle. A retailer who sells a poisoned medication is absolutely liable, as is the manufacturer who produced a fallible tamper-proof seal (which is worse than no seal at all).
Feel free to elaborate on why you think I'm wilfully ignorant.
If by my second point, you're referring to circumventing the tamper-proof seal on medications, then maybe you'd like to expand? Manufacturers, retailers, and medical staff are (jointly) responsible for medications for their entire life cycle. A retailer who sells a poisoned medication is absolutely liable, as is the manufacturer who produced a fallible tamper-proof seal (which is worse than no seal at all).
Feel free to elaborate on why you think I'm wilfully ignorant.