Q1 Answer: Online registration has not changed the rules associated with dropping or adding a class. The only difference is that you have the ability to drop or add a class online rather than through the traditional registration process. If you drop a class after a certain period of time, you may or may not receive a refund (either partial or full). See the bulletin or other documents such as your course syllabus to determine the date. Also, you can only add a class up to a certain date as well.
Students may not drop a class after the class withdrawal date. This is usually 75% of course instruction. Students may add a class after it starts, but will need authorization signatures. See Dropping a Class and Adding a Class under the Registration information found on the CMC web site for additional information.