Here the FDA regs say a company can certify a product as gluten free if it contains less than 5 PPM (Parts Per Million) The celiac websites have mixed results for true celiacs. Some can tolerate that small amount and others not so well. They also have mixed results for the reaction to alcohol and vinegar (wine and cider vinegars are fine, but not malt vinegars) Non grain based alcohol (rum or true potato vodka, etc.) is safe but not most whiskies.
As I've posted before, my daughter's a celiac, as well as another distant family member and their doctors both recommended throwing out all their old dishes and cooking pot, pans, utensils, etc. to avoid cross contamination. Eating out is virtually impossible. many restaurants offer a gluten free menu choice but they cook it on the same appliances they use for the regular menu and then serve it on the same dishes.
Yes, gluten free has become another fad for those who don't truly need it. That's been both a help and a curse for my daughter. It helps because there are more GF foods available now: GF pastas, breads (the GF breads are truly awful but the pastas are pretty good) The curse is that b it I mentioned about eating out. When she asks the waiter about how they prepare the food they ususally assume she's just one of the fad group and brush off any questions or even lie outright.
That said, going gluten free doesn't mean she has to eat more processed foods. Quite the opposite; it means she has to avoid them because gluten get sneaked in through the most surprising ways (through vinegar, soy sauce, seasonings, etc.) The GF pastas I mentioned are pretty good but they are processed (just lijw regular pasta) Instead she usually uses spaghetti squash or rice rather than pasta. Fresh veg rather than canned (processed) etc.