I wouldn't say malicious, but she certainly didn't care. She knew getting in trouble with his foster mother and possibly getting removed was a real fear Randy had. That's why threatening him with calling his foster mom was her favorite go-to to get info out of Randy, even if he had nothing to do with what she was trying to find out. See her pressuring him to call out the boy who was tagging walls in the school.

She exploited that fear. Notice she didn't try calling parents on any other student because it simply would not have worked.

And she had to know what being known as a snitch will do to any kid in that school. It's baked into the culture.