Under the Truth in Caller ID Act, FCC rules prohibit anyone from transmitting misleading or inaccurate caller ID information with the intent to defraud, cause harm or wrongly obtain anything of value. Anyone who is illegally spoofing can face penalties of up to $10,000 for each violation. However, spoofing is not always illegal. There are legitimate, legal uses for spoofing, like when a doctor calls a patient from her personal mobile phone and displays the office number rather than the personal phone number or a business displays its toll-free call-back number.