the children would be frightened

From Prince Caspian by C.S. Lewis in chapter 14: HOW ALL WERE VERY BUSY.

A teacher who doesn’t see:

She clutched at her desk to steady herself, and found that the desk was a rose-bush.

A teacher who sees:

She looked out of the window and saw the divine revellers singing up the street and a stab of joy went through her heart. Aslan stopped right under the window and looked up at her.
“Oh, don’t, don’t,” she said. “I’d love to. But I mustn’t. I must stick to my work. And the children would be frightened if they saw you.”