I was just wondering...somewhere in the blue course outline sheets, it said we were not allowed to switch out of our cores? However, on SOLAR it is giving me the option to. What is the deal with that, am I actually not allowed?

I think they mean that if you're registered in a particular core, you shouldn't attend a different core (two reasons: # of seats, and the fact that your iClicker entries will only count if you use it in your scheduled core).

But on SOLAR, you can definitely switch them (i.e. register yourself in a different core) if it suits your timetable better.