Alice and Bob live in a flat together. Bob mentions to Alice, that he is buying and reselling merchandise but not reporting it to the tax office, because he does not want to register a business.
One day, Bob leaves the flat but leaves his computer turned on and the door to his room open. Alice looks at the monitor, sees the evidence for tax fraud in the online selling/buying history and decides to take pictures of it to report it to the authorities.
Is Alice within legal boundaries?