How disappointing for your friend.
I am always so hesitant in dealing with any sorts of marks or stains ... so no help here.
She had the right idea ... just the wrong product.
You might want to tell your friend to use Painter's Tape the next time.
It is "safe" as it doesn't leave the residue behind that you get from masking tape.
I use it in oh so many ways in my sewing room.