I wondered about this. I got glutened last weekend. I was at a different grocery store than usual. The employees were definitely baking there, and the bakery was right next to produce, where I did most of my shopping. I walked out with my clothes and hair smelling like a bakery. Went home, ate leftovers from the previous night's dinner (all prepped at home from fresh whole ingredients), slapped on some sunscreen, and went out to a park with my husband. About an hour later I started getting an awful headache, then brain fog/fatigue, stomach stuff, etc. Symptoms for several days. I thought maybe the sunscreen, but I looked online and the particular Coppertone product I used is safe. I've got no other possibilities besides the grocery store. Scary, scary stuff. I've never gotten sick at a grocery store, but then I've never been in my usual stores when they've been baking since going gluten-free.
My husband went gluten-free at home except for beer (which is fine- beer doesn't get all over the place like bread crumbs do). He only eats gluteny things at restaurants or other people's houses. He doesn't have any problems from barley/rye beers, but we're noticing that if he consumes wheat for more than a day or two in a row (usually in the form of sandwiches or pizza at lunch), he starts feeling sick. He's had odd food intolerances since he was a child, so I'm starting to wonder if he's been wheat-intolerant all along. We eat better than ever now and we're both feeling better, so no complaints from him about the diet.
I haven't had any problems with quinoa either in grain form or in the pasta, but that doesn't mean that you couldn't be intolerant to it. I think people can develop intolerances to just about any food, especially those of us whose illnesses have damaged our intestines.