There's a practice that seems more common than ever: sending paper copies of documents already submitted online.
I don't know why this is being done, but it defeats one of the nice things about having an online application, which is having less mail to open and less paper to process. Many counselors seem to be enclosing a copy of applications that have been submitted by their students online, many students are sending copies of essays, and many teachers are sending duplicate recommendation letters.
Online applications are supposed to streamline the process. However, if we have to handle two copies of everything, the flow of documents is significantly slower. Trust the online process! Know that if there's a problem, we'll email you.
Which reminds me...please keep checking the email account you gave us on your application. You can update it if it changes, but that is the primary way that we will contact you if there is a problem.