XXXX out serial numbers

[Brazos]

I am 36 and have been around guns my whole life. Something I have noticed even when I was a kid reading gun magazines is that that serial numbers get partly Xed out. For example I write in to a magazine (or a thread such as this) and say "I have an old Colt 1911 with a low serial number NM34XXXX, What is it worth?" Obviously there must be some sort of protection for the owner of the gun by partly Xing out the serial number. What is the fear of listing the whole serial number?

Thanks,

Brazos

 

[VARifleman]

Registration as well as someone calling in that it's stolen.