I had a similiar experience to you CC, on the Dean Forest Railway, where I work. We had a diesel multiple train running, and it was advertised on the leaflet as this. When we got into to Lydney, a couple came on and the Spambot said "This is a steam railway, isn't it supposed to be steam?" and I said "No, today we are running diesel". She then said "But you are supposed to be running steam, look, it says 'Steam Railway' on your leaflet" to which I replied "Yes, but sometimes we run a diesel day, look here on the leaflet" and I showed them the calender with the little sign that says diesel day on the day we were running. Then she said "Oh well. I'll have to complain, I wanted steam". I was like
it says right in front of you 'Diesel Day'??