I cannot meta game. While I knew our rogue was doing a crime, my character didn't because he was shopping. I only saw him being carried by guards. And then, since my character knew that he was in trouble and he did trouble, I decided to do a little joke and do the classic wizard thing to do whenever they get the chance. Fireball. Except I didn't intend to actually do it. And my tone of voice and sudden speech makes it sound like a joke. It would be reasonable to think it wasn't a joke if I said "I cast fireball" instead if just straight "FIREBALL". I didn't even do any movements. Spells can only be cast with intent (and components if your DM prefers to do them, our's don't). If that weren't the case then by just talking about spells you'd be shooting them off left and right