TLDR Don't be a jerk, and don 't use code you have previously worked on.
1. You cannot work on your project before the event begins. You can brainstorm, make designs, but not write any code.
2. You cannot use another team's source code. You may only use what is available publically to everyone.
3. The decision of the judges if final for determining prizes and awards
4. Please comply with all instructions from Product Hunt hackathon organizers.