Prevent MySQL from entering implicit defaults into non-null columns

I am trying to use multiple attachments (in one statement) and I have this table structure

CREATE TABLE Scores
(
  studentID varchar(50) not null,
  score int
)
ENGINE = InnoDB

My request:

INSERT INTO Scores Values
('Barry', 45),
(NULL, 41),
('Jones', 53)

This statement (I was expecting) should fail because the [StudentID] column is not NULL. The problem was that MySQL entered an empty string ('') in line 2 ... and allowed the rest to continue.