Could it be for something OTHER than skin colour that Scott said "Lock your doors"?

When those black boys on bicycles were passing by?

Maybe he saw someone match their description and thought they were petty thieves and maybe the area has been burgled a couple of times before by people who ride on bicycles and he, however unnecessarily and over the top, decided to take precaution without worrying too much about political correctness?

Also, maybe the lock was on her side or maybe not, but I think he could've locked the doors himself, no?

Even if at the very least it was stupid and pompous and unpleasant and unprofessional of him to act like that in that scene.