But why not a billion dollars? The worst that happens is someone has more than they need. And then what happens?

One of two things:

1: It sits in the bank, where it's lent out for investment

2: It's spent, possibly on something optional but still legitimately useful and non-frivolous, in which case it flows back out into the economy

I don't see a bad outcome..!

That would be a massive redistribution of wealth, much more than needed. The billion wouldn't end up being a billion though, due to runaway inflation.

People who win the lottery often end up worse off than when they started. Giving everyone a multiple of the highest lottery winning every year would be destructive.

Of course it's nonsense. And if you articulate why, I think you would see that your basic income argument is nonsense for mostly the same reason.

I'm probably just preaching to the choir, so you can have the last word if you want it.

No your point specifically is nonsense, because its a false comparison. Having a basic billion dollars would be massive wealth redistribution, as opposed to minor, and would have many additional negative consequences due to the severity of it.

I'm sure there's some useful academic term for what you're doing here.

Appeal to ridicule? http://en.wikipedia.org/wiki/Appeal_to_ridicule

I think it's called "reasoning" or "logic".