In L4D series for example, they don't use any Normal Maps on the Zombies for their folds and such, they make clever use of Diffuse and Specular, so as said, it all depends.
Some stuff here http://wiki.polycount.com/BodyTopology Especially check out the Brian Tindall and Jonathan Williamson links... for example Tindall's http://www.hippydrome.com/LLeg.html
It's now five years old, so there are some differences - but fundamentally it's the same. UT3 lacks lightmass and landscape, and has a lot of material nodes missing, as an example.
'Forms' and 'shapes' are just the visual simplification of anatomy. The Asaro Head is a great example of this. Anatomy is like the hard science behind why the shapes and forms are the way they are.
This is an interesting one, please email support@marmoset.co with example files (.tbscene and meshes) so we can add it to our bug tracking system. Thanks!
They do it for some DRM (example: http://store.steampowered.com/app/9860/ ) but not for everything, I think. @ McGreed - you don't mean irony, you mean sarcasm.