Are talking about this? https://en.wikipedia.org/wiki/Blue_Pill_(software)

It happened in 2006 and never happened after that. I would consider it as secure as it gets.

Sorry, can't recall the exact lecture... It was only interesting as I was looking at a toy project to see if metastability issues were solvable. Practically speaking, it only proved the folks at Sun were very smart people choosing an encrypted mmu. =3