Imagine, if you will, that your eyes don't work as well as they used to. (Vision impairment is one of the most common types of disability; statistically speaking, it will happen to you as you age, if you don't already wear corrective lenses.)

While enjoying the brand-new library at Kenyon College, you are confronted with what SHOULD be a stairwell, but you can't see stairs, just handrails and a weird shimmery pattern where the stairs should be. Do you try your luck, and stick your legs out into the shimmer? Or do you search for the elevator?

I'd say it was almost equally dangerous for person with that high level of visual impairment to use any stairs where each stair is a single uniform color.

In your example it might be difficult for such a person to identify the location of the stairs, but still very dangerous once they found them and began climbing. In my example-- say the stairs were a uniform red-- once the stairs were found it would still be equally dangerous to climb them, little better than going up blindfolded as you couldn't distinguish one stair from another.

A person with that impairment should probably want some sort of occupational therapy to use a guide cane or other method to safely perform tasks like that without relying clear contrasting colors.

Think Parkinson's. Visual clues as to what is or is not immediately in front of you can seriously impact your ability to make the nerves in your leg muscles work correctly.

Now, that said, maybe no one with Parkinson's should be going up any stairs of any sort. But I think glass stairs, even if frosted, would definitely be an ADA problem.