Vendors at festivals and markets should be NPCs only
There's currently a flea market in my San Myshuno, and out of 2 vendors, both are MY sims, not NPCs. I dislike this so much because what they are selling has no relevance to what they do for a living ...
They actually gain items. Sims that are assigned these jobs will actually have all the items on the craft sales table assigned to their household inventory.