How does that solve anything? She'll just use it on her own account... At least this way OP was able to see what their sister was up to.
Fixed that for you. And it will get shittier as investment dries up and the pressure to monetize increases.
The fact that we use the LLM should always be preceded with, "I know I shouldn't be doing this but..."
And if you are a parent or a big brother, you absolutely have control over what online services a child uses.
What an insane world we would live in otherwise.