I notice many new posters will enter their cells phone number in the Wireless/Device description when they sign up.
Could that box have a comment posted stating DO NOT LIST YOUR PHONE NUMBER and once they click in the box it would disappear. And if by chance they do enter their number the system recognize it is all numbers and not accept the entered information.
I am sure most are not aware when they enter their number it is their for the world to see.
OR change the title to, 'Enter your phones make and model here'. That would be easiest.