photo finishes and dead heats

I've been wondering about these dead heats like we saw on the weekend, and then decisions in races like this year's Melbourne Cup. And about photofinishes in general. Nowadays the call can depend on one pixel's difference between horses.

When a pixel can decide who wins and who comes second, how sure are we that the starting gates, which are towed up and down between races of different lengths, are totally fair to all the horses? What I mean is that, if they are even just a centimetre or two skew, it could make the difference.

And how accurate is the finish line? It was put in place before photofinish cameras were in use (on most courses, that is), when dead heats were decided by the judge's eye. Is it accurately laid at 90 degrees to the straight ... when a pixel can make the difference?

What do you think?

Mav feel many should be a dead heat