This nifty little quest gives no rewards except for scenes.
In Balamb Garden's Cafeteria, as you go into the Cafeteria there's a table with three students sitting at it, with a Trepe Groupie nearby. Their dialog changes as the story progresses, with the following ones being available:
-Before the SeeD Field Exam.
-After the SeeD Field Exam but before going to Timber.
-After visiting the MD Level but before going to Fishermans Horizon.
-On Disc 2, anytime after visiting Fishermans Horizon.
-On Disc 3, before the Trabia Canyon sequence.
The key is to speak to them until they start repeating the same line. If you do this all five times, after returning from Trabia Canyon they'll have become full-fledged SeeDs; otherwise, they disappear for the remainder of the game.