The kidnapping rules state:
You have to have a roleplay reason to attack the victim in accordance with the DM rules
I find the deathmatch rules to be somewhat of a gray line, it states "Deathmatching is the attack of attacking a player without a proper IC motive and interaction." I'd argue that the social dynamic of a prisoner and their guard is an IC motive, in a real life setting I find it ludicrous that a prisoner whom was planning an attack/kidnapping would not commit to this plan on the basis that the guard did nothing wrong.
I'm also confused on how you're supposed to get hostages for a prison robbery if you are limited by DM rules, it's not like you can walk around waiting for somebody to do something that would give you DM rights, that's ludicrous. I feel like either I'm missing something about this rules somewhat fundamental or the rules need a change.