Sure, but "can't" is a strong thing to say, when actually the result is thought to be legally untested.

You have to understand where "can't" comes from. It's a multi-layered system. If the government says you can do it one way and then the corporation's lawyers tell them to do it that way, corporate policy then becomes that you have to do it that way, and you therefore "can't" do it some other way.

This is why government regulations often create perverse incentives and unintended consequences. You can't just consider what the rule says, you have to consider how people are going to respond to it.

This is why e.g. the DMCA takedown process is widely abused. Do corporations have to execute obviously invalid takedown requests? Maybe not. Are most of them going to, when the consequence of doing it is harm to powerless third party individuals and the consequence of not doing it is potential liability for the corporation? Yup.