"That they haven't found such evidence yet does not mean that ID is not science"
All sorts of goofy things get taught in school by teachers.
Here's my hypothesis:
It's not a hypothesis. It's a straw man. But I'll play for the sake of argument.
The universe is supported on the back of an immense tortoise. You cannot see it because you are part of the universe and cannot see beyond its reaches.
What reason do you have to believe that either (A) the current theories of how the universe works are inadequate to explain the universe or (B) the tortoise exists? The problem is that you can't honestly answer these questions because your example is a straw man. A ID advocate or even a biblical literalist could honestly answer these questions, even if you don't find their answers personally persuasive.
Now, I'm going to begin lobbying for my theory of the universe to be placed in every textbook used in our public schools. You cannot demonstrate that my hypothesis is incorrect, and I claim that it is correct. I haven't found the actual evidence yet, but one thing's clear:
If you can muster thousands of supporters who honestly believe in the tortoise and want their children taught about the tortoise in school, then by all means lobby away. That's how democracy works -- power lies in numbers. Of course if we had effective school vouchers, a lot of this problem would go away and Fundamentalists could send their kids to Fundamentalist schools, Atheists could send their kids to Atheist schools, Tortoise people could send their kids to Tortoise schools, and so on.