The average in-shape 70kg person can produce 200W for a more than an hour on a bicycle (source: http://en.wikipedia.org/wiki/Bicycle_performance)
Ever sat on a bicycle in a gym with a wattage meter? It is actually very hard to only produce 125W on a bicycle. On the road you'd go very slow and risk falling over, and in the gym the pedals almost spin faster than your legs.

And of course Lance Armstrong can do that. I am a "recreational" amateur cyclist who does no more than 2500 km/year and can maintain more than 250W for hours. It's not difficult.

I can tell you why: anonymity
In stock trading systems, bank transactions, etc., all parties are known in one way or another. Depending on the techniques used, if something goes wrong, the party that's wronged can prove who they are and that something didn't go as they directed.

That doesn't work with electronic voting, since it is supposed to be anonymous. There are many reasons for that: full freedom in casting your vote (no employers, governments etc looking over you shoulder to check that you voted 'correctly'), and also not being able to prove what you voted for, to avoid vote-buying (you can pay for a vote but you'll never know what you paid for)
It is very hard to build anonymity into an electronic voting system, and still have the same degree of tamper-proofness as a paper ballot.

It should be noted that in the Netherlands, you have to color a circle of approx 1 cm diameter red. It is easier to see what the intention of the voter was than with hanging chads.

Erwin