I would think this is a failure of the client, which should support compression formats well enough to be able to fish around inside of the compressed file once it got the metadata portion (zip directory or whatever).
http://en.wikipedia.org/wiki/Zip_%28file_format%29#Design: A directory is placed at the end of a .ZIP file. This identifies what files are in the .ZIP and identifies where in the .ZIP that file is located. This allows .ZIP readers to load the list of files without reading the entire .ZIP archive.