I don't think it's right to put these instructions 'if' the theme is old, let's target the Codex resource at the larger community and if someone needs help with a specific theme they can post on the forums.

I'm just seeing a lot of people creating Child Themes with the `@import` line commented out and they're wondering why their styles aren't being loaded in.

This modification wasn't clear enough for the community.

http://codex.wordpress.org/index.php?title=Child_Themes&diff=145568&oldid=144786