I never have those traits selected on my sims and I get the mischief skill anyway from the sim either coming into contact with another sim that has the skill or by trolling the web.
That was just for "trolling the forums" file, as for the rest of Mischief actions...
Ya, annoyingly enough some (if not all) autonomous actions work on all sims no matter traits and likes/dislikes. They only have slight desire/preference calculation differences. But it isn't enough for 100% prevention, for example simply being in a Playful mood up ticks the chances of a Mischief action... It is hecka annoying. They need to overhaul autonomy.
