I think I mentioned it in another thread: Starro (the same guy who was telepathically controlling nine galaxies worth of sentient beings, and who made Despero's TP seem non-existent) was unable to telepathically manipulate so much as a single Czarnian cloned directly from Lobo's DNA.
Point being: Lobo has extreme resistance to TP. Not sure how Cass compares to Starro in that department, though.