Can't they just use auto-graders? I got the impression that for many of my CS courses, the TA and professor labor went mainly into creating assignments and lectures. But many of the assignments were self or automatically grading. If you have suitably lab-based assignments, then it shouldn't be too difficult to lower the cost of adding more students into the lower level courses.
As mentioned in another thread (http://news.ycombinator.com/item?id=2444557) this course, like MIT's equivalent, is very TA intensive and is using undergraduate TAs (although I should note that MIT's 6.01-2 are not suitable for non-majors).
ADDED: I just found out that enrollment in MIT's 6.01 just jumped to 380 this spring from 250 last spring. As noted, you don't by and large take this course unless you're seriously considering EECS as a major....
So it looks like Stanford's experience is mirrored at MIT.
