Ignorance leading to mistakes

There is an advertisement in Greek television using "Ederlezi", the soundtrack of a famous movie about Gypsies, as its theme, in an attempt to create a sad atmosphere supporting the scenario of the ad. What they didn't know is that Ederlezi is actually an optimistic song, celebrating the springtime. So, I don't understand their choice. I suppose that they found its sound quite melancholic. Lucky them the greek audience is ignorant too!