It's different because the students have control (topic, depth & breadth, time management), and given the right atmosphere and guidance, will have increased ownership and investment in their project. Ideally, students will also have input about the expectations and assessment, including the possibility of a successful project despite failed idea.

Secondly, you can allocate creativity in time slots, it just takes time. Given consistent and predictable blocks of time everyday or a few times a week, students or anyone else will get better at using said time. You get used to it; you get better at context switching into the necessary mode and, importantly, since it's predictable your brain will also consider and prepare outside of the designated time blocks.

The difference in my mind is that you are not graded on the documentation or the presentation. Therefore, you are not being "forced to do it" for an extrinsic reward. But I do understand your point. As teachers we are still bound by time and curriculum.

How are you keeping the students accountable if they are not being graded? I'm not attempting to criticize the idea (I'm rather interested in it), but I'm curious how you deal with the student that says "I'm not being graded, so I'm not doing it."

This question did come up in my class. I said "if you do not want to take this opportunity seriously and would rather be graded on an assignment, I'll gladly assign you a different project for the rest of the year that I will grade you on." He stayed with the 20% project.

The accountability is in the documentation and the presentations. More of a peer accountability than anything else (which I think is powerful). I'd be happy to hear any suggestions!

Sounds like a reasonable policy. I'll be curious to hear how it all turns out.