I had GF pizza without cheese when our ski club had a gathering. Didn't have any problems. I ate salad too (before anyone touched it, as sometimes that causes issues), and the waitress seemed to work very hard to check dressing ingredients for me. The place was extremely busy, so I was so worried- I think that gave me a little tiny feeling of indigestion/gurgling, but it never turned into any of my other normal IBS exposure symptoms. Maybe part of that was eating my first meal at such a high altitude.