Well, my idea is I might actually pay them the money. You say they are asking for a code in order to give them the funds in the first place? Odd. $12 for a single short is out of the question, but for the bundle (only around 4 look interesting), that not too bad.
edit:
It might have something to do with their system of Passes. It appears to be a screening service for movies and shortfilms, screened in some official capacity for members willing for pay a flat rate for the whole thing. This is just a guess. Here's a link to their main site with passes:
https://cicff40.eventive.org/passes/buy
Chicago International Children's Film Festival. Passes are a bit on the expensive side, unless you were highly interested in the entire catalogue. The site still seems to be advertising the passes for its 40th anniversary, which has now passed, according to its own banners. I'll look into if there's a way to get a more direct access to that bundle of 7 shorts instead.
edit 2: sales for the passes are locked to, unless you have the code.