A little suggestion for Threadless
Just thinking out loud here.
FACT: Giving your competition a low score increases your own chances to win.
FACT: Some designers are compelled to do just that. You know who you are.
A logical suggestion:
The designers whose submissions are actively scoring at the moment, shouldn't be able to score others' submissions. Or their scores shouldn't count towards the final. This way the voting will be fair and impartial, and your average scores will be much higher.