<<Disclaimer:  Verify this information before applying it to your situation.>>

My 6 year old celiac daughter has eaten McDonalds french fries for years and
has never had one even slight reaction.  If indeed they do use the same oil
to fry the french fries as they do the hash browns (which I know have flour
in them), first of all, they are not fried at the same time, and second of
all, the cross contamination from the oil would be so minimal in my opinion
as to not be a concern.

She also consumes products with distilled vinegar without consequence (I am a
great believer in the scientific findings presented on this list by Don
Kasarda)...and additionally, I am speaking with her doctor at UCLA Medical
Center right now about the possibility of introducing oats into her diet
(based on new findings from a study in Ireland).  Keep in mind that my
daugther had a definitive celiac diagnosis through endoscopy & biopsy at 16
months and has been thriving on a gluten free diet...both on the height and
weight chart.  She still reacts extremely acutely to minute amounts of gluten
(pernicious vomiting) which she has experienced on a couple of occassions.

So, I have to disagree with your warning about McDonalds...and agree with
Jane Davis.