From that article:

> Koh frequently remarked on the similarity between each company's tablets. At one point during the hearing, she held one black glass tablet in each hand above her head, and asked Sullivan if she could identify which company produced which.

> "Not at this distance your honor," said Sullivan, who stood at a podium roughly ten feet away.

I get what you're saying, but they were asked to tell the difference over an unspecified distance.