An apparatus and a method for preventing a user from bypassing a viewer blocking system that uses program related information, such as content ratings, included in a program signal. The present invention prevents the user from exploiting the time delay associated with detecting, decoding and comparing the program related information by switching channels to observe portions of objectionable programs before the blocking system can react. The present apparatus comprises a processor (110) which provides an output signal (RGB OUT) derived from a selected program signal (VIDEO, VIDEO IN, AUDIO IN) of a selected signal channel and prevents or allows user access to the output signal in response to a determination of whether a user selected program blocking criteria is met. The processor modifies the output of a selected program signal upon user selection of a new signal channel if a default blocking mode is selected by the user, then continues to modify the program signal associated with the newly selected signal channel at least until the program related information is determined.