Whether she was working crew or nobody, she was correct. So, need to be a bit careful how you handle things.

I would not engage. But, I would have ceased the violation.

If she wants to complain to a working crew member and that crew member takes the position that you were violating a lawful crew member instruction, e.g., the announcement, and complain to the Captain and the Captain wants to re-open the aircraft and have you offloaded, I suppose there is that risk. But, seems minimal.

So, shut it off and ignore.