I know people who have varying degrees of gluten intolerance but not celiac. For most it's in no way life threatening. One experiences bloating and bad gas if he eats a bagel; another has to sit on the pot all day if she accidentally ingests a saltine's worth of gluten; and a couple have conditions in between.

For the latter, avoiding gluten is pretty much a necessity. For the former, it's a choice, but one I can understand asking for some accommodation for.

There are also apparently gluten allergies other than celiac. I know someone who when exposed to gluten gets the sort of reaction that some people do when they eat peanuts - he keeps an epi-pen on hand because if he accidentally ingests some his throat will swell up, airways will shut down, etc.