it`s just a little inpulse Robert... well, with "controversial" I mean that you have to be careful with your choice...
for example the methode of rewards: this won`t lead to links that last longer. If you promote that you offer an iPad or something like that for just a referral you might loose this link after the competition is over ... furthermore if you request a link from each participant Google might interpret this as buying links if they recognize it.
If youve got an onlineshop for example it
s much more difficult to initiate successful linkbaits...
The most difficult aspect with linkbaits comes up when you try to convince other webmasters. Try to imagine their position (you already mentioned that): why should they put a link to your site? There are many reasons to do not.
Let me quote another example: there is friend of mine who created a 40-pages PDF which explains how dangerous a fire can be and what to do to avoid serious injuries etc.
He created a landing page especially to promote that little ebook which is for free! Then he figured out the webmasters of all the local fire departments and told them about that PDF. They liked the information and what he did. They regarded his work as very useful und linked to the landing page of this book... successful linkbait I would say.
Other webmasters are not interested on what you do or what you`ve done unless you can provide something very useful...
Sorry for not telling you the perfect solution but this depends on your project, you know?