Do not know if this is still common practice in Ul'dah, but way far back in the Eorzean timeline, its hinted that the slave trade and especially the sex slave trade was quite a popular and prominent trade in Ul'dah and Limsa to an extent. Modern or current day Eorzea seems to have something akin to indentured servants now instead of slaves, though its not a solid theory or idea considering the Flame General himself was a slave gladiator fighting in the Blood Sands at one time and won his freedom when he was much younger.
