I'm not sure i understand: do you mean i should scan my files, in case i share a file which would infect a Windows box? If so, i don't think i care. If you mean something else (i.e. somebody planting evil files on my "share"), please elaborate.

I also stated i do not run external-facing services. That applies to the Samba example, too (although i was fibbing: i allow keypair-only login via sshd).