[gentoo-user] emerge --update behavior

[Michael Orlitzky]

Using "emerge --update foo" adds "foo" to your world file. This is 
responsible for pretty much every package that incorrectly found its way 
into one of my world files.

Is there any reason to desire the current behavior? I'd like to suggest 
that it be fixed, but want to be sure I'm not just being short-sighted.