In 2000, I was working at an NYC restaurant (Josie's on Third) -- it was a new non-dairy health-focused organic-everything restaurant. The waitstaff was trained in all the ingredients and many of the sources and were highly conscious of needs of our customers. We were tested on it a staff meal.
One day, two friends sat to dine... we brought bread and our non-dairy spread. Customer asked "what is this?" I replied, "it is red-pepper tahini, an alternative to butter". I take their order, tend to other tables and arranging beverages, when I come back around 5 minutes later the table is empty. I ask my manager "what happened?"
The lady had a severe sesame allergy and was rushed to the hospital -- *she did not know that tahini was sesame paste and I did not tell her*. I have no idea what happened to her and I think about this several times per year.
For the last 15+ years, I have been a hands-on operator of complex computer systems operator. This experience has absolutely shaped how I communicate with teams, how I look at how failures may happen, how to expect the unexpected, etc.
I now have a son with peanut allergies. It also influences how we dine. It is not easy and I'm glad there's out-of-band solutions like these drug therapies. We are not there yet, but might consider it.