McCain staffers stole 12,000 miniature American flags from Obama's convention and then lied to people at a rally, pretending that the Democrats had thrown them out. They were actually being bagged and stored for later use.

http://blogs.denverpost.com/opinion/2008/09/06/republican-recycling/

The Democrats hate America so it would be only natural that they would throw those flags away.
Reports say that the original plan was to burn the flags in the middle of their convention floor.