If the code stated that no RA grills in the kitchen area's only then I would agree with you, but the code states closets,bathrooms and there are very low percentages that a fire will start in these places. Another point is that if this was to stop the spread of fire then there should be a fire damper in the supply air registers in the kitchen area.

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Well thats my 2 cents.
Brian Kelly
Kelly Home Inspections