I should probably take Marisa's upbringing into consideration. She was likely encouraged to lie, cheat, and steal by her role model, so even if something's free, she'll steal it anyway. Marisa was probably taught to kill as well, but it appears that murder and the anti-Hakurei rhetoric didn't stick.
Miched said:
USE THE DOORS!
Mimama taught her to make her own door post #829887.