If I were attacked by an individual, unprovoked as aikido is a "nonviolent" martial art, I would be able to disable the attacker or defend my self long enough to escape.
have you give thought on the whole "nonviolent" martial art? kinda contradiction in terms. i assumed that you have seen youtube videos of aikido? can you imagine what it would like to a body that gets thrown into a concrete paved street or a tree or a moving bus? using the earth to hit someone isn't what i would call "nonviolent".
as far as exercise goes, i go the gym to get extra workout on my non-aikido days. and wearing bright neon color body suit to the gym, in order to blend in, is highly recommended. please post picture if you do.