It seems likes kids only do what you tell them not to do, so this advice may seem wise. However, this is a form of confirmation bias; adults notice when kids don't listen because mainly because they usually do.
If you tell someone a student some skill is difficult, they will believe you. You have set them up to expect failure. This expectation is easy to meet, and most students will give up early.
If you tell a student something is easy, they are likely to believe you. Believing a subject is easy, they are more likely to follow through to mastery because they have been set up to expect success.
Reverse psychology is a trick. Tricking students is a way to alienate them; it may work on the few, but the many will respond better to affirmative attitudes.

Its both. Its a double-entendre. They inflate themselves by implying that they only accept bigwigs, but also, that these people are beneath them. These guys totally disrespect their clients: c-level surely means in their minds means average, at sea-level, ie dipshit.

Take a look at http://singularity-university.org/.

They have 3 programs. The one that makes the news is the graduate student program with 30 students total.
But if you are 'interested' you can send them your CV over internet. Is this because they are actually going to accept random applications from internet to fill 30 spots?
Of course not. They are going to deny you the big prize by implying that you are not good enough, and then offer you the 10 or 3 day 'executive' programs.
Yup, you are going to learn how to achieve the singularity in a 3 day 'c-level' executive seminar.
[The hubris of calling your potential clients 'c-level' boggles my mind]