In many restaurants the so-called tip is applied, I agree since the service deserves it, buying an ice cream like this does not include it, however there are those who give something to the person who serves it and brings it to the table.
When I bought this ice cream I went to the cash register and paid for it, then they called me to pick it up, this service does NOT include a tip and I have NOT seen anyone give it, I would say that it is a normal service and does not merit it.
I have entered the restaurant several times to buy pizza, when I ask for the bill they ask me if it includes the tip, note that they always ask the question, in the bill is not included, I always include it, generally the service is very good, it seems fair to hand it over.
A simple plate of bacon, the question is also asked when asking for the bill, the tip is generally 10% of the value of the meal, but in small places it is what you want to deliver.
We already know that a food like this asks the question ¿ does it include a tip? It is 10% of the value is something we all know, in conclusion: I agree with the inclusion of the tip, in some small businesses it is directly for the person who serves you, knowing that I helped a person in some way motivates me to deliver it......I wish you a happy day.