Nightwing has a little more tact than that. Mostly from his years away from the Bat and his city and realizing that, well, Batman's way just didn't really work for him. Besides, these are (shock and awe) normal people, apparently, and probably wouldn't appreciate a grown man in his twenties just appearing out of nowhere in their house. Robin can get away with it because . . . well, he's Robin and really, his entire purpose iss being able to get away with things like that.
All things considered, though, it is still a little strange to be walking up to the front door of this completely normal-looking little house in the middle of suburbia -- in costume -- and not be there on business.
He gives the Reyes a charmingly disarming smile and holds a hand out to Jaime, "I hope we're not late."