gnome-design-team/gnome-mockups — comment on commit 60cae6e0ca6ff25d3ac8d0179ec1b3e41c313b49
File:  line 0
By jimmac:

So apparently your default is not the default. Mouse should be relative by default -- http://git.gnome.org/browse/gnome-settings-daemon/tree/data/org.gnome.settings-daemon.peripherals.wacom.gschema.xml.in.in?h=gnome-3-2#n90