Cool TIL about mdutil. I still cannot disable it as mdutil seems to be having trouble parsing the path to the share. Ive tried in bash/zsh/sh with all quoting/escaping patterns I can think of and I must be missing something.

(shows up in in `mdutil -s -a`)

  /Volumes/Backups of Saucy's MacBook Pro:
     Indexing enabled.

  sudo mdutil -i off /Volumes/Backups\ of\ Saucy's\ MacBook\ Pro
  Error: could not resolve path `/Volumes/Backups of Saucy’s MacBook Pro'.