Just catching up on the latest no-fuggly info & saw the part about the Downtownies being generated from pre-made templates.
That certainly explains why mass-spawning Downtownies always netted me a batch of 3-per-look Sims! (As in there are 3 of each template spawned, resulting in a Downtown overrun by a mass of various triplets!)
It's weird that Maxis went this route for Downtownies. The weirder part is that you can make them yourself in whatever clothes you choose in CAS (using Inge's teleporter to make them Downtownies) with no ill effects.
Silly, silly Maxis....