You're right on this point. But there are ways to build interfaces that sidestep this.
Run a sanitized VDI with no local storage --> offshore independent entity (e.g. a Hong Kong Company) that holds the AI service contract and API license --> GLM-Legal.
Yeah sure but your clever sidestep is just "hiding evidence from the court." The kind of person that feels the need to have a secret AI lawyer is also probably going to just tank their case in another way.