Perhaps, but this has already happened actually. When they suddenly decided with the novels to go on a killing spree on the main EU characters lineage in ABY +20-25 because it suddenly added drama (well drama is good but you have to know when to stop), the decision was actually made by the publisher and the authors that were working for her at the time. The characters that got killed were actually characters belonging and created by previous authors, like Timothy Zhan. And I read that the latter was quite pissed when he heared of it, but he just said he was disappointed... After all, what could he possibly do besides it ? Legally, all those authors own nothing. I'm not sure there is special intellectual property laws in the US besides your usual copyright laws. And copyrights are owned by the ones owning the rights to the license, which is not the authors.
For people not afraid of spoilers i'm referring about this :
[spoiler]With the Vong saga they suddenly got the idea to kill a main character, but not the too important ones, but sufficiently important because he was part of the original trilogy : the sidekick, aka the wookie. It went all drama and all, with Anakin Solo blaming himself for his death, and they decided that they liked that. A bit too much, so they started to kill off everyone, starting with Anakin Solo (to much anger of the fans), and then proceeded with other characters like Mara Jade, killed by Jacen Solo turning loldark, and the killing of Mara Jade, who is a character that originally appeared in the first Timothy Zhan's novels back in 1992. Well, Chewbacca was liked because he was an original character from the trilogy, Anakin Solo was kindof liked because he was cool, but Mara Jade was a very popular icon, and her author was as you might guess not quite pleased when they decided to kill her off without even asking him first.[/spoiler]