Brilliant Ideas That Will Never Work: voters have to know what's in their own interest

Once upon a time I proposed a simple knowledge test for voters, and anyone who can pass the test can vote regardless of age.

Today I have a better idea: require all voters to know which proposed policies are in their own interest. I've seen quite a few people both in Canada and in the States (when your neighbour spends like 18 months shouting on the rooftop with a bullhorn "Look at us! We're having an election!" you tend to notice a thing or two) supporting candidates or parties who stated platform is directly against that person's own interest. Basically they're saying "I have size 11 feet. The Purple Party wants to ban shoes that are larger than size 10. Vote Purple in 2008!"

I wish they could administer a test to every prospective voter: "Name any party's or any candidate's position on any issue, and explain why this position is or is not in your own best interest." People wouldn't be required to vote for a party or candidate that is necessarily in their own best interest (maybe you agree with the Purple Party's premise that large shoes use too many resources and are willing to go barefoot for the greater good, maybe you're 82 years old and own enough shoes to last the rest of your life), they'd just have to be aware of whether a particular policy actually is in their own best interest.

The only problem is, apart from the logistical problems of administering a quiz (and an essay question at that) to every prospective voter, you could never get everyone to agree that the test is being administered fairly and neutrally.