[tsimionescu]

I don't think these techniques are often applied to problems in tests - there are other, simpler ways of catching cheaters there.

They are much more likely to be applied to homework assignments, where the opportunity for copying is large, but the chance of two students producing the exact same >500-1000 line program is slim to none. Perhaps once in a while a critical function will be copied and no one will realize or similarities in a trivial function will be unnecessarily flagged, but this will be relatively rare and quickly discovered in manual review.