Some people have tried pouring hot coffee over it to make a sort of ad hoc affogato, but according to reports, this did not work as the coffee froze on top instead of melting the ice cream.
That is cool, ice cream frozen hard enough it'll be just right to eat when you get home (as opposed to having to get home, and wait for the ice cream to re-freeze)
You know what. I'm glad it is a thing. Because this is one of those hidden cultural nuggets that unless you lived there on the regular you would never know
Pro tip from a seasoned domestic train traveller from Finland: don't you go nowhere without a camping spoon/fork combo. Got a random military surplus one and travel has been smooth ever since. (Also have a table knife, a wooden mug, and a thermos mug. Oh and a Swiss army knife, but that's just regular every day stuff.)
Now I'm curious what the difference is between ad hoc and non ad hoc affogato, because pouring hot coffee over ice cream sounds like a standard affogato to me