It’s great that Safari (and every other sane web browser) blocks pop-ups. It’s not so great that Command-K toggles the blocking. I’ve turned it off by accident a number of times, probably when trying to use Command-K in the Finder, where it means “Connect to Server”.
About a month ago I found a hint on how to remove the shortcut:
defaults write com.apple.Safari NSUserKeyEquivalents -dict-add "Block Pop-Up Windows" "nil"
Handy.
13 July 2004