Factual error: At one point, Frank Lucas is speaking on a public telephone. Visible in the background is a poster with a web address on it (ends in .biz).
Factual error: At the start of the movie, as Bumpy and Frank enter an electronics store, Bumpy mentions Toshiba products. However, the company was, in 1969, named Tokyo Shibaura, and the name wasn't changed to Toshiba until 1978.
Factual error: In law school, Richie Roberts is asked to take the prosecution's side on US vs Mead. The actual case, United States v. Mead Corp. was not argued in the Supreme Court until November 2000.
Factual error: Early the movie, the maroon 1972 Monte Carlo at the intersection in the background is sporting wheels from a 1984 IROC Camaro Z28.
Factual error: When Ritchie was following the driver with $20k into NYC, the scene shows the GWB entrance heading to NJ.
Factual error: A few moments after the 20% rent deal for $1 in the cafe you can see a 747-400 (or later) in the sky, the winglets identify it as such. The 747-400 had its maiden flight in April 1988. That scene plays in 1968.
Answer: The idea is if cops wouldn't take a million dollars for themselves, free and clear without risk, they are impeccably honest. Therefore, they wouldn't accept bribes and probably not hold still for shakedowns or payoffs. They wouldn't cover up drug or weapon planting and would testify against crooked cops.