"...weren't built ahead of time." Where's the line for this? Surely I'd be permitted to reuse libraries (that I've written; that I got from github; whatever) and perhaps the "project" is a smattering of glue. Am I disqualified because 99% was written "ahead of time"?
libraries are fine of course. in higher profile and more competitive hackathons, i've seen quite a few teams who complete the whole project (or re-use the same project from another hackathon).