Please feel free to brainstorm.
Since that this kind of ATM could have a receipt, why not consider having a receipt lottery?
I think receipt could further encourage people to use this ATM and go on ramp besides the burning mechanism built inside BitShares.
And different formula for receipt lottery could be tried: tiny prizes with lots of winners (and higher expectation to win), or large prizes with only a few winners.
This is a great idea if implemented correctly. Also, make sure to use the winners to advertise your project.
You probably want to make the pay outs be few but large, yet you need to balance that with the ability to pay out on what I'd say would be a weekly basis. Then make sure to interview the winner each week whenever possible and use that content to make it seem like there is a higher chance of winning than there really is. If you think about it, that is one of the main things marketing does--cues repetition and emotion-inducing stimuli along with a product.
Winning a large amount seems more likely if all you ever see is content showing how much people win. Add onto that a recruitment program that increases the payout as more people join and volume cme to the system, and maybe you have a winner.
Behavioral Hueristics my friends...one of the reasons I see most of marketing as a game of illusionists' creation. Much prefer education