In some climates if there's been a bad year, or an inexperienced beekeeper harvested too much honey, it is sometimes necessary and normal to feed bees with sugar in autumn/winter to prevent starvation. This shouldn't make it into the honey harvested on spring and summer.
Or to keep hives alive when nectar is scarce but colonies have not started to hibernate. Adulteration of produced honey with syrup would be 10x easier than feeding bee with syrup and then doing extraction from comb.
