I'm not sure what you mean. Do you mean that someone can send a file to you without you d/loading it?
The answer is no,
but(big but
) if you d/load a virus, you could find yourself with a whole slew of files that you didn't d/load. Though technically they weren't d/loaded, they were created by the virus. Be careful what you d/load, especially program files(exe, zip, ect).
See:
http://www.gnutellaforums.com/open-d...uld-aware.html