Jack,
I find it very, very difficult to get parents to supplement with
anything other than a bottle.  Most inexperienced parents (and health
professionals) are horrified with the idea of supplementing with a cup.
They are afraid that the baby will choke to death.  The problem with
SNSs are cost, although some of my colleagues at a local hospital have
rigged up a home-made one for peanuts; reluctant mothers claim they are
"messy" and time consuming.  From my experience, an SNS won't work on
a baby who refuses the breast , screaming and throwing his body back
every time the mom tries.  SOme of my clients have been willing to use
the new Medela softcup which seems to give the security of the bottle
with less nipple conrfusion.  I've also had decent results with a
trainer type cup, especially with older babies.

Susan Nachman-Srebrnik, IBCLC
Ranana Israel