Letizia's skirt and Felipe's uniform initially made me think they were in Grenada, the Caribbean island.
"It started as a purely military celebration, but became with time a more colourful and popular event, the central acts of which are held each year at a different city."
I'm unsure exactly what people think Letizia is supposed to wear to an outdoor event in southern Spain in June when it is hot enough for Felipe and another high-ranker to be in dress whites. (Other than a hat, for her own sake, but they don't do those.) There is clearly no dress code: is she more or less suitable than the woman in the bright red coat?
She looks tidy, presentable and unobtrusive, and I don't see how muted flowers are inappropriate or strange when they are brought for military personnel all the time.