In the 1972 case Federal Maritime Commission v. Seatrain Lines, Inc., the U.S Supreme Court ruled in favor of Seatrain Lines, a shipping company that had been accused by the Federal Maritime Commission (FMC) of violating the Shipping Act. The FMC claimed that Seatrain was unlawfully charging different rates for transporting similar goods and providing preferential treatment to certain customers. However, upon review, it was found that these practices were not discriminatory as they did not result in any undue or unreasonable preference or advantage nor did they subject any particular person to any unjust prejudice or disadvantage. Therefore, it was concluded that there had been no violation of Section 16 First of the Shipping Act which prohibits such actions.

The dissenting opinion in the Federal Maritime Commission v. Seatrain Lines, Inc., case argued that the majority's decision to allow Seatrain to operate its terminal facilities exclusively was incorrect and not supported by law or policy. The dissenters believed that this ruling contradicted the Shipping Act of 1916, which aimed at preventing discrimination and promoting fair competition among shipping companies. They also pointed out that allowing such exclusivity would lead to a monopoly situation where one company controls all aspects of a particular service, thus stifering competition and potentially leading to higher prices for consumers. Furthermore, they disagreed with the majority's interpretation of "just and reasonable" regulations under Section 17 of the Act; arguing instead for an understanding more aligned with public interest considerations rather than private business interests.