They absolutely will send you home. We lost one guy in my interview group straightaway due to this, plus another whose 1st class medical had aged beyond six months. Two more were dropped after the written test. Another guy came all the way from Hawaii, but didn't bother to wear a suit. He was dropped after the sim. In all, only two of seven received the offer that day.

Come prepared and the interview process won't be a big deal. If you're unprepared, it won't last long.

Ken