Originally Posted by Mercenary Pen
Except that, having already betrayed the king of Faq to further her own ends, she presumably has a very low loyalty rating... and could in theory turn on Stanley at any time. She's achieved the end that required her to stay loyal to him (attuning an Arkentool), and now has equal or greater power, and might break away.
While Wanda probably has a very low loyalty rating to Stanly (she is loyal to fate magic), she actually didn't betray Banhammer. She thought that Stanley was an idiot (he is, but a powerful idiot is the problem) and that Faq's forces would make mincemeat of him. She was VERY mistaken, but she never intended Banhammer or Faq to come to harm. And it would have netted Faq a Arkentool if it had worked.