The practice of deliberately saying you did not witness any controversial incident, just to avoid either further discussion, or any involvement.
In post match TV interviews, whenever Arsene
Wenger the manager of Arsenal
Football Club is asked about a controversial incident, where say one of his players committed a bad foul, or handled the ball for which the referee didn't award a free kick, he always says; "I didn't see it."
Despite it happening immediately in
front of him, when asked by the
police if he'd witnessed the accident, the driver went "All Arsene
Wenger."