I never really thought too much about the logic behind "shut up, you're going to jail" line until now, mostly because I love that line. It's such a Batman-y line, and was kind of refreshing to hear that in a movie where he murders with a smirk. It seemed indicative of some kind of growth, so I buy the idea that he was trying to make an appeal to Selina.
Also, in Batman's defense, he didn't specify when
Schreck would be going to jail, haha. Maybe he was planning to beat/intimidate a confession out of him. He is Batman, after all.
Us Bat-folk sure do know how to split hairs over this type of stuff though, eh?