What happens if I'm placed on a waitlist for college courses? Is it a bad thing?

[mynewhome]

I'm an International Student and I will start in the fall 2015. I also need to register for the courses soon.

Now I'm scared that I'm placed on a waitlist for courses...what happens if I would be placed on a waitlist and wouldn't be able to get off that waitlist until the start of the semester?

Does that mean that I'm not registered for any course and not allowed to attend the college in the fall 2015 (even if I got accepted to the college for fall 2015 and my study permit also starts in the fall 2015)?

Thank you