How could she bear to do this

What a monster!

Hopefully they got a picture beforehand, if not then I would've killed her

Because I'm assuming she's a teacher who gets paid to teach, and that uses that board for teaching purposes?

Although this may be beautiful. It is impeding learning especially if they needed to use the board. Also it is a distraction albeit a fantastic one

Even beauty is transient.

This reminds me of a great art series by Phil in the Circle. He created a bunch of art that had to be destroyed. Called it Goodbye Art if I'm remembering right

fake. no eraser is that effective at removing chalk

Maybe she made it