I would hate to see someone withhold information because they are “anti-tax.”
That would depend on the law of whatever country the claimant is in, assuming it would be a non-US citizen making the claim.
Assume US Citizen, US tax law.
Since it’s such a massive amount of money, and such a massive hazard to the snitch, I suppose you ought to consider the status of the estate tax in the conundrum. 
A lot of people are “anti-tax”, what does that change? Why wouldn’t it be taxable?
What would be the tax on a reward like that?
Good question.
With American tax laws, if you didn’t pay the tax on the Bin Laden reward money, you would probably be sentenced for tax evasion and be put in prison longer than Bin Laden himself.
Tax law often provides incentives for people to do or not do certain things. Many people think taxes have a “punishing” effect (i.e., punishing success). Perhaps tax law should encourage and not punish people for helping the government cathch evildoers. Maybe this is why it shouldn’t be taxable.
I have heard lottery and game show winnings have a special tax provision. Would any special tax provisions apply to rewards for catching crooks?
It does not make sense for a person that anti-tax to be interested in helping the authorities catch Bin Laden. This anti-tax person is opposed to the government advancing society’s interests, and as such, it can be assumed that person would be unlikely to want to help the government advance society’s interest in catching Bin Laden. If you live outside a major east coast or west coast city, Bin Laden is unlikely to be a threat to you personally.
Don’t worry about taxes, worry about staying alive long enough to collect. Even odds on a fatwah being declared against the dude who gets him.
Depends where you live. Here in California, winnings from the state lottery are not taxed by the state (there are still federal taxes, however). I have friends who have won money on gameshows (Jeopardy, Who Wants To Be A Millionaire) and IIRC they did have to pay taxes on those.
I assume that the lottery exemption is because the state gets a percentage of the ticket sales (about 33% here in CA, last I heard) and another 50% of the sales goes back out in the form of prizes. They’ve already collected their share of the winnings, so to speak.