Of course Mary used reddish highlights before, as well as coloring her hair a very dark brown at times.
But this color is a drastic step from brunette, albeit in different shades, to being a redhead... and in my eyes, it's a totally ill-advised experiment, resulting in quite a disaster.
Neither does being a redhead flatter her coloring, nor is this a very appealing color in itself - a strange mix of copper and mahagony, which unfortunately is bound to turn rather lighter and even more brassy in due time.
I hope she realizes the mistake and executes some damage control. Back to classy brunette as soon as possible is the only way out here, IMO.