Under the Junk Fax Prevention Act of 2005, the sender of an unsolicited advertisement sent to a person's fax machine is still liable for a minimum of $500 per page, and damages may also be trebled at the court's discretion upon a finding that the violation was willful or knowing. A "willful" violation is simply one that is "volitional", while a "knowing" violation is one that occurs when the senders actually knew "or should have known" that he was potentially breaking a law, even without specific knowledge of the law.