No, the difference between eveining and night is the joke. Picture a gentrified urban area. Who is out and about in the evening? Couples going out to dinner, friends meeting up for coffee or window shopping, parents taking their children out for ice cream, whitecollar coworkers grabbing a drink after work before heading home to their families. Picture the same area at night, who is out and about? Sketchy people. Drug dealers, crackwhores, drug buyers, drunks looking to score their next drink, and people just generally up to no good. So he's saying that if he does see a prostitute, he at least does so at a respectable hour; he's not the type of person who would be out seeking a prostitute at night (while implying that the judge is).