I think its exactly that, spoke to a friend the other day who doesn't like boxing but has bought into the hype and build up for this, he reckons Mayweather isn't taking it seriously and McGregor will win.
I think it's exactly as you say, to try and sell tickets to those who know its a complete mismatch. I think one or 2 of the Sky pundits have been asked to talk McGregor up for the same reason.