When =net-misc/networkmanager-0.9.8.0 starts it switches on wireless interfaces. Previous versions of networkmanager did not change status of wifi when starting. It looks like it was much more reasonable behavior.
I think you should report this directly to upstream and post link here for tracking: bugzilla.gnome.org
Reported to upstream: https://bugzilla.gnome.org/show_bug.cgi?id=700995
*** This bug has been marked as a duplicate of bug 457940 ***