Lugano Tourist Traps

I had done some research before we went to Lugano and had found out that you can pay in Euros in the town, although there might be some risks. We decided to do that because we thought it would not be worth the hassle of changing money for just one day, but in the end I wished we had done differently. It seemed to us that a heavy charge is added if you pay by Euro, but you are not told so in advance.
When we wanted to have lunch, we first had a look at a few restaurants, but we found them to be too expensive and also we did not really see anything we would have liked to eat. Unfortunately, as it was a sunday, all the smaller restaurants in the centre were close, and only the big ones at the lakefront were open - of course they are incredibly expensive. After some time, we decided to try Burger King (yes, usually we don't eat at these kind of places, and I never do at home, but I think from time to time it's ok on a trip). We wanted to order some water, a small salad and chips each - and we were shocked when the girl working there told us that this was 32€!!! Sorry, 32,00€ for a meal in such a fast food place???
We asked about this and she said that the usual price for this meal would be about 27€, the rest was the charge for paying in Euros... But we had another check, and according to the information outside, the meal was not 27€!
We were not ready to pay so much, so we left again and after some time we found a McDonalds and finally had lunch there. It was more expensive than a usual McDonalds, but still ok, about 14€ for the both of us (water plus salad plus chips).
The crowd of customers at McDonalds was not a usual crowd, there were many different people, even many who were elderly or looked quite distinguished - this clearly showed us that there were many other people who were not ready to pay such high prices.

I think next time I would take the trouble of changing Euros to Swiss Francs if I went to such a place, just in order not to be subject to such hidden service charges.