The repurcussions happen mainly to the site offering the download if they don't have a disclaimer to not download if you live in the U.S. Nobody's been hauled off for using Decrypter to back up their personal DVDs.
Close, it's not illegal to make backups but it's illegal to break the encryption codes (macro vision et. al) that prevents you from backing them up. SmartRipper and DVD Decrypter both circumvent encryption.