Can I crash a class if I'm not on the waitlist?

<p>So I registered for four classes today am pretty happy with my schedule. I got the best profs and stuff, and I'm taking a mostly honors classes. I can fit one more easy class (philos 100) and this would be IGETC transferable. Perfect right? Well, turns out I can't register for more than 16 units, and adding phil 100 puts me at 17 :( There's only four seats left in the class but I dont't even think I can waitlist with more than 16 units already on my schedule. Apparently we can move up to 20 units after the semester starts, but if the waitlist fills up as well should I just say forget it?</p>