@FridayJones - duh! Yes, 'involuntary' is legally loaded! So's 'coercion'. I'm leading towards non-voluntary. I don't like "forced", because the inclusion was much for the same of children, where actual 'force' isn't really necessary.
Re the cause of them watching the "live recordings": if someone is so messed up that they get hold of material like this, then repeatedly watch it for a long period, I would suggest that whatever messed them up enough to watch it over a long period is going to be the primary diagnosis anyway.
If someone is messed up, and gets into a situation that causes PTSD, that doesn't disentitle them to the diagnosis. Eg. Someone has a psychotic episode and decides they need to chop off their arm with a circular saw. They'd likely have trauma issues from that. Does it really matter if that psychosis was schizophrenia or drug-induced?
The same logic applies to ptsd from viewing what are real and extreme recordings of human suffering, over and over, for a long time. We're starting to cross too far into moral judgement I think to say, "if you did that because you're a junkie, you aren't entitled to the diagnosis".
It's important to remember that we're not talking a few too many graphic news bulletins. Whatever put you there, watching that stuff "frequently and for a prolonged period" is going to mess you up. You don't 'disentitle' women who are raped because they dressed like a hooker and acted like a hooker. Same goes here - this is extreme viewing. You can't not be effected by it, whatever your reason for watching it.