I agree, Storage isn't that much of an issue these days and six web cams around the place feeding into portable USB drives is pretty simple to set up with a RasPi these days. Then you have the chance of adding a face to the police report as well.

WTF? There are systems for doing that task specifically, why would you want to build one from scratch?

Well assuming the Hackathon is on a razor thin budget (which I grant you it may not be) might be able to support adding some equipment which can be tasked to other things when not hackathoning and can be installed/removed in a variety of venues. The WebCam/Pi/Disk system is about $100 (less if you use the Pi's camera module).

You absolutely could go out and buy a video surveillance system of course.

So that you can incorporate plausible deniability, selective disclosure, and secret-sharing based quorum. Do you really want to have created a system that gets subpoenaed for automated guilt-by-association when it turns out that one of the participants is being investigated for thoughtcrimes?

FWIW, building this out with a Pi is a trivial task and would probably end up much cheaper/more flexible in the long run.