The systems used are typically not up to discerning small differences, like that between AIFF and .wav or FLAC and .wav. Give them a good system and make the listeners close their eyes and you would get the result you expect, even with untrained listeners.
Training ears is always a good thing. I believe it mostly allows the listeners to tune-out the visuals and focus more on the placement and focus.
Steve N.
Empirical Audio