Depends, but I think Splik hit the nail. If there's an obvious secondary gain other than treatment or attention for their "condition", then I do feel comfortable calling it malingering. Otherwise factitious works just fine.
Was recently watching a Forensic Files 2 episode about Donna Perry. Previously went by Douglas Perry and murdered 3 women in the Spokane area in 1990, had gender reassignment surgery in 2000, and was arrested in 2014 for those murdered. Tried to claim that she shouldn't be held responsible because she was now a "different person" and that it wasn't really her back then and was eventually convicted.
Relevant because in the episode they showed a clip where she was being interviewed where she was indignant that she was being charged with the crimes when she supposedly wasn't even the same person. The officers response when asked if she was responsible was, "...yes, the body is responsible for the acts it does" which found to be quite a perfect response from someone with undoubtedly limited experience for that situation.
I mean one issue is, which is why I can get behind the policy being "fair," is that if you "KNOW" you have alters and they "do" things outside your control, then what responsibility do you have for that knowledge? To that end, maybe it does make sense that they are seeking to be committed or whatever.
If I know I have a condition I don't have great control over, like narcolepsy or alters, then I have a responsibility to make sure other people don't get hurt because of this thing I know about with potential to cause harm. This could mean not driving or not owning guns, or getting psychiatric care.
My point being, that these people don't seem to understand that the very ability to say "My alters did it" means you have awareness, means you have responsibility.
The only people that would have a rational argument otherwise, can't make the argument because it would only be true if you had an alter you knew nothing of and "they did it," in which case, you would never be able to deny the crime saying "my alter did it."
It's like that silly saying, if you think you're crazy you probably aren't because crazy people by definition don't know they're crazy.
If you know about your alters, then you can't use the defense "but my alters did it" and act like you have no idea, because you can only say that if you did know.
This comes up a bit in the cases where someone goes off their meds and then commits a crime, or does drugs blacks out and commits a crime. Somewhere in this series of events you had some responsibility and control or foreknowledge.
Even in the case of someone with an "actual" alter, how often does the person dissociate to the point they never notice lost time or anything weird? Has no inkling whatsoever help is maybe needed? I'm sure Splik has an example and I know that not being aware of dissociation can itself be part and parcel of said dissociation, but how common is that really and how common is there were no clues to you that there was anything wrong with you, and to the point where serious harm to another person was done?
It doesn't change anything. Sadly, if you have an "alter" and it ****s up your life, you are still left holding that bag. It's no different for the bi-polar patient that has an episode and catches an STD and gives it to their wife. There are consequences despite the best of intentions because of the reality of your life. Sadly harms to others are not always a product of intention.
What's more, if you really were to be believed you had an alter you either knew nothing of or had no control over and it did dangerous things or killed people, wouldn't we even more than the "average" criminal who claims responsibility and agency, need to incarcerate you or whatnot if for no other reason to protect the public from your alter?
As far as what other people owe you, I mean if your alter beats me up, maybe I should in theory forgive your primary personality, but I still can't invite you over for dinner and you're going to have to accept that having a condition doesn't mean other people are not entitled to protecting themselves and this may mean consequences that are not comfortable for you.
Just saying, so much of it even taken at face value doesn't end up being as much of a great excuse as people might seem to think.