To complain or not to complain: Restaurant Etiquette

Years ago, I remember sitting in a restaurant with 5 friends horrified because 3 out of 5 sent their meals back.  There wasn't anything wrong with the restaurant -- it was pretty decent actually -- but my friends had managed to find something.  One didn't like the way his meal tasted.  One thought the chicken was too overdone.  The last  wanted more of the side dish and wanted to speak with management.

I cowered in my corner and hoped my meal didn't come with the spit like I knew theirs was about to.

I tend to go the opposite way.  Not what I ordered? Well, what came looks good, so no big deal.  A little overcooked?  Well, that's just like Mom's home cooking.  I survived years of that.

I will say something if there are bugs or hair.  Usually.  But I try to be really nice about it.  No point in getting anyone upset.

Now I have reached a new conundrum.  Since I've been diagnosed with Celiac's disease, eating out is a mine field.  I might make it through my meal without a problem or, I might take a wrong step and *BOOM* explosion of symptoms.

Restaurants are a lot more aware now than they were even a year ago.  They try to be educated about what I can and cannot eat.  They make special allowances for food prep and -- more times than not -- the manager comes out to assure me they are taking all precautions.  And yet, sometimes, I still get sick.

I rarely, if ever, tell the restaurant about my reaction to their meals.  I figure they did their best and sometimes things happen.  However, the chef in the states who served his patrons gluten in secret and then "outed" them for being fakes makes me rethink whether or not I should be letting them know.

But how do you call and tell a manager that his food gave you gas?