To quote from the referenced URL at fedora-docs-list:

I would like to see <example> sections take on a different rendered
style, somewhat like the <screen> sections. I think the right way to
do this is with an outlined box, but without changing the shade (BG
color). That should keep an <example> distinct from a <screen>.

Tammy agrees here:

http://www.redhat.com/archives/fedora-docs-list/2004-September/msg00125.html