To guess or leave blank, that is the question.

I''m prepping for Exam P in May (hitting a 6.8 Earned level on ADAPT!) and today my boss (MAAA) and I were talking. He's -older- and hasn't touched exams in years. He gave me the advice that if I don't know a question, leave it blank because at least I get .005 of a point (or something, I know it's not an actual point).

I swear I read something recently that stated guessing isn't penalized in the slightest and guess if you need to, leave nothing blank!

Can anyone confirm do I guess on a question if I 100% do not know it, or do I leave it blank?