The real answer to what happens when you wire speakers out of phase is your dog will circle clockwise when laying down instead of counter-clockwise.
I can provide this smart-a$$ response because one semester back in college I had wired both speakers in this manner and didn't notice until it was time to tear down to move out at the end of the semester. Lack of notice could have been induced by beer but I thought I was sober when I hooked it up.