?ספק דרבנן לחומרה

What's even more interesting is that on the same web site (but presumably from a prior year), it says:

Quinoa is not one of the five grains that can create chametz (wheat, oat, barley, spelt and rye). Nonetheless, there is a difference of opinion among Rabbinic decisors (machloketh haposkim) as to whether quinoa is considered kitniyoth (Ashkenazic custom is not to eat kitniyoth on Pesach). We suggest asking your local Orthodox Rabbi if it is or is not kitniyot. here

On the one hand I'd want to tell the OU that the public is watching and knows what you're doing, but on the other hand, I don't know what they're doing.