Interesting
I see what you are saying, by the very definition of the link text 'surprise me' or 'lucky dip' etc, then it's not really blind, as the surfer knows it's a lucky dip type of thing.
I wouldn't use it on a freesite, or a page specifically geared towards a specific sponsor, but on a landing page where you have a choice of sponsors and/or pages selling a particular sponsor, then a link on the page saying 'surprise me' or 'lucky dip' whatever may generate some interested clicks. On such a page it doesn't matter than the link is blind anyway, so that's kinda moot.
On something as specific and targetted as a freesite, is there any reason you'd want a surfer to 'wander' off, physically and mentally, rather than keep him focused on selling the sponsor in question?