Let's say the best model on a table happens to be a yellow '56 Chevy, and a few modelers decide individually NOT to vote for it because
1. It's a Chevy. The worst Ford model is still better than the best Chevy model..,
2. they don't like yellow cars.
3. they don't care for that model's particular style (factory stock, or pro street, or drag, or stock car...)
4. they know who built it, and hate everything he does.
5. they found "better" models on the table to vote for.
6. The builder is not a member of their club, whether the club is the host club of the contest or not.
7. they have no clue as to what a quality model "looks like".