For those reasons, Fifa provides exceptions case-by-case — and Australia have taken advantage.
"Approximately 40 exemptions [have been] granted since the coming into force of the relevant provision in [the] summer of 2008," a Fifa spokesperson said.
"Typically, member associations of countries with an immigration tradition are applying for such exemptions. Australia [has] submitted by far the highest number of requests, [with] more than half the applications submitted by [them]."
Germany, Ireland, Denmark and the US are among other countries granted multiple exemptions.
Bernie Ibini is one Australian example. The former Central Coast and Sydney FC attacker was born in Nigeria but moved to Australia when he was a year old.
The FFA had to provide several letters from the Nigerian Football Association and other documentation to satisfy the Fifa processes.
Polish-born goalkeeper Alex Cisak (Leyton Orient), Ghana native Kofi Danning and Scottish-born Cameron Burgess (Fulham) are others to have gained a clearance by Australia in recent years, while Awer Mabil is an example of the patience that can be required.
The former Adelaide United player, now in the Danish Superleague, was born in a Kenyan refugee camp before moving to Australia aged 11, after his family was granted asylum. Kenyan authorities had no record of his birth and it took more than a year for his dispensation to be processed.
"Each application can vary, depending on specific elements," said the spokesperson. "Also the cooperation of the requesting association is an important aspect. The time needed for a proper assessment can vary considerably."
Fifa said there were no ongoing proceedings for potential breaches of player eligibility.