I'm sure people have thought about this before, but I just read a part of Gathering Storm where Tuon is musing on whether an Aes Sedai could be forced to use the One Power as a weapon. The third oath is: "Never to use the One Power as a weapon except against Darkfriends or Shadowspawn, or in the last extreme defense of her life, the life of her Warder, or another Aes Sedai" Obviously they can be forced-- one way is by forcing them, their warder, or another Aes Sedai forward into danger from an enemy and then coercing them like any other enslaved channeler. But is there an easier way? Is a knife to the throat and a threat to kill them if they don't attack with the one power "the last extreme defense of her life?" Obviously the slavers would be reluctant to do this because they don't want to kill their slaves, but would it be effective? At one point in the early books (unless this is a show-only scene and I got confused) Egwene is unable to pick up a pitcher because she thought of it as a weapon. Could a similar trick be used, such that an Aes Sedai who has been enslaved is tortured or brainwashed until she believes anyone who doesn't serve the Seanchan Empire is a darkfriend, thereby enabling her to use the power as a weapon almost indiscriminately?

Not terribly interested in arguing about the definitions-- I disagree with your definition, but it's not relevant to my complaint-- you get my point, they said they did it to motivate Moiraine. I don't know if it counts as a hint. They've been playing fast-and-loose with the Oath against killing "unless they're a darkfriend, or in defense of her life or her warder's life or the life of another sister" this whole time. If we're taking that execution as a hint, then what do we call it when Moiraine took out half a Seanchan fleet in the last season? I don't know that there was any more depth to the scene that I was giving it. They said they wanted to give Siuan a big speech and motivate Moiriane. That's what they did, and they cut a really time-consuming subplot. You could argue that it was a very practical choice. But her getting dead impacts Moiriane immediately and obviously and for the Tower it mostly just cuts off the cruelty and the torture that Siuan's speech emphasized. All it tells us about the Tower is that they are down with torture (which, no shit, everyone in this series loves torture) and they are merciless to darkfriends (which, no shit, so is everyone in this series).

It is accurate that Laila got fridged. If you would like to add an arbitrary and additional distinction to the term "fridging" which requires that the character have been created solely so that they can die and motivate another character then I sincerely apologize for failing to fully engage with your vernacular and would like to restate my complaint as follows: What the FRIDGE, they killed of Siuan to motivate Moiraine and provide extra emotional depth to her fight with Lanfear and that is a stupid waste of a character and of an extremely talented actress and I DO NOT LIKE this narrative decision!

Did you watch the little post-credits interview thing for the last episode? They were pretty explicit that they killed her off because they thought that her storyline in the books wasn't worth Sophie Okonedo's talents and this would give more emotional depth to Moiraine's fight with Lanfear. Killing off a character to motivate another character is the definition of fridging. You can argue that killing her off to motivate Moiraine is a better use of her than marrying her off to Gareth freakin' Bryne, sure. But I don't think that changes the fact that's she's still there, headless and chilly.

They fridged Siuan and said it was to give her character something more important to do, the stupid rat bastards. Scheming her way to revenge on Elaida as a power behind the throne [ahem] I mean loyal adviser to Egwene IS something important to do dammit!