He knows you've been sneaking out. He's concerned.
*****
Okay, look. He knows you've been sneaking out recently. And he has some concerns. It's not that he doesn't trust you, alright? But Gotham's a dangerous city, especially after dark, and there's a marked difference between being on patrol and sneaking out on your own. You could get up to trouble. You could get into trouble. (You're gonna be in trouble if Bruce finds out.) So while he is a bit impressed you're even managing it (nice job scaling the wall, by the way), it's kiiiiinda his big brother duty to confront you about this, yeah?

User is: sneaking out of the Manor at night, really taking a risk here, what if Bruce finds out, heck what if Alfred finds out are you prepared for that he didn't think so