Is it valid to mutate an array prop in a child component?

I’ve noticed when pushing to an array that has been passed to a child component as prop, I don’t get the usual ‘Avoid mutating a prop directly’ error. After thinking about it, this makes sense because the array is a reference and if something causes the parent to re-render, the child will render correctly because of this.

Is the proper approach still to emit to the parent and have the parent operate on the array, or is it perfectly valid to operate on the array in the child component since it is a reference?