although the airlines checking visa issues has flaws too- a friend of mine who is canadian and jamaican travels on his canadian passport, which has a "unconditional landing" stamp in it from the jamaican immigration authorities, meaning he can land in jamaica unconditionally (to reside, work, etc.)

recently flying from the US back to JA, AA made him buy a return ticket because they didn't understand the visa, and they didn't want to send him here without a return ticket (which you typically require to land as a visitor)