We use random people for 1/2-second scenes or just add 3D models of characters in later (we already made several models so all we have to do is make their animation and add them in)
The guy in tuxedo at the end is a model as well...
As well as this:
http://outsparkclub.com/file/pic/gallery/1583.jpg
(for 16 and older)
If you never saw the "How much do you love noodles" video you won't know what it is.