False Gift/Magical Air

If a putative apprentice merely has "Magical Air", when/how does the Master knwo this, on opening? after opening but when starting to train spells/arts? never? a simple InMe spell that I have missed?

Bob

Hedge Magic has a spell that can detect the Gift. It's an InVi spell, and is 20th level. It's a 20th level spell with a concentration duration but can probably be designed as a 15th level spell with momentary duration.

Barring that spell being cast, I'd certainly would have it understood early in the season of Opening the Arts.