Because, as usual with that kind of question, it's not that simple.
Let's say an user asks ChatGPT to get some info about something and for some reason it starts using exploits in the background to get them from a server. Should the user be responsible or OpenAI?
Okay, lets go with that as scenario #1.
For scenario #2 lets use "developer asks an agent to a self-hosted LLM to get the docs for a ERP system, and it hacks the vendor to get unreleased and undocumented docs".
We'll assume, for the sake of this argument, that in neither case did the user intend for any malicious action to be performed.
> Should the user be responsible or OpenAI?
In scenario #1, the agent+LLM is under the control of OpenAI, not the user, so OpenAI is liable.
In scenario #2, the agent+LLM is under the control of the user, so the user is liable.
There is no scenario anyone can come up with that is not addressed sufficiently by existing laws[1].
It's very clear, and it's only getting muddied because there's a group of powerful people who want exemptions from the current law.
IOW, the only reason to draft new laws for AIs is to exempt their usage from the current laws.
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[1] Possible 3rd option (local agent + OpenAI LLM). In that case an investigation would determine where the culpability lies. Just like how it is currently done in law.
When a pressure-cooker explodes and kills someone there are only two possible liable parties: either the user or the manufacturer. An investigation determines who's liable. I see no reason to automatically exempt everyone from liability just because an agent did something.
I have lost track of the metaphor, but man pressure cooker lawsuits are more common than I thought.