[TrackerFF]

Much easier to prove the case of terrible jokes or non-PC behavior. Twitter has streamlined that stuff for years now - and what's more, that kind of behavior is much more relevant for more people, rather than academic fraud which might be a very niche thing, only relevant to small circles of people.

One could ask - why is it that petty theft can land some people behind bars for years, while wealthy people committing tax fraud only get fined, or at most a couple of months in a cushy white-collar crime facility? Well - for one, the former crime is much easier to prove, especially if you're caught red-handed. The latter crime tends to be incredibly complex, and will cost a ton of resources to prosecute.

I guess the same goes for your questions. Professors incriminating themselves on twitter or youtube - easy as pie.

Collusion rings with respectable professors, that probably use students for dirty work and plausible deniability, and resources enough to fight their employer in the courts: hard fight