When you're grading a large number of students you may not notice duplicated code unless you happen to go over the duplicates relatively close to each other. Furthermore, in the classes I TAed we had multiple TAs, and we would split the students amongst us. So even if two students' assignments were identical we still wouldn't necessarily notice, as different TAs might be looking at each one. Automated tools help even when you're already going over all the code manually.

MS Lock in? What MS lock in? I've watched The Guild and never once did so through anything Microsoft.

They sell DVDs of seasons 1 and 2, and I assume will do so with 3 once it's done. And the eps are posted (officially) to youtube a while after they're released to Live.

Oh, and that song they did is on both Amazon MP3 and iTunes.

So while they do use Microsoft for some distribution, it's not locked in at all.