GH-Why can't Alexis tell Kristina that Anthony is bad?

I know this wouldn't exactly solve the problem, but she was complaining to Sonny that Kristina thought Anthony was a nice man in a wheelchair. Can't they tell Kristina to run from him if she sees him. My father wasn't a mobster, and my mother wasn't a DA, but I still knew not to talk to strangers and to run away if approached by one. Plus can't they let the nanny in on the danger so she can be on the lookout.